2012
Calvo, Hernan L; Perez-Piskunow, Pablo M; Roche, Stephan; Torres, Luis E F Foa
Laser-induced effects on the electronic features of graphene nanoribbons Journal Article
In: Applied Physics Letters, vol. 101, no. 25, pp. 123508, 2012, ISSN: 0003-6951.
@article{ISI:000312780000098,
title = {Laser-induced effects on the electronic features of graphene nanoribbons},
author = {Hernan L Calvo and Pablo M Perez-Piskunow and Stephan Roche and Luis E F Foa Torres},
doi = {10.1063/1.4772496},
issn = {0003-6951},
year = {2012},
date = {2012-12-01},
journal = {Applied Physics Letters},
volume = {101},
number = {25},
pages = {123508},
abstract = {We study the interplay between lateral confinement and photon-induced
processes on the electronic properties of illuminated graphene
nanoribbons. We find that by tuning the device setup (edges geometries,
ribbon width, and polarization direction), a laser with frequency Omega
may either not affect the electronic structure, or induce bandgaps or depletions at +/-(h) over bar Omega=2, and/or at other energies not
commensurate with half the photon energy. Similar features are also
observed in the dc conductance, suggesting the use of the polarization
direction to switch on and off the graphene device. Our results could
guide the design of novel types of optoelectronic nano-devices. (C) 2012
American Institute of Physics. [http://dx.doi.org/10.1063/1.4772496]},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We study the interplay between lateral confinement and photon-induced
processes on the electronic properties of illuminated graphene
nanoribbons. We find that by tuning the device setup (edges geometries,
ribbon width, and polarization direction), a laser with frequency Omega
may either not affect the electronic structure, or induce bandgaps or depletions at +/-(h) over bar Omega=2, and/or at other energies not
commensurate with half the photon energy. Similar features are also
observed in the dc conductance, suggesting the use of the polarization
direction to switch on and off the graphene device. Our results could
guide the design of novel types of optoelectronic nano-devices. (C) 2012
American Institute of Physics. [http://dx.doi.org/10.1063/1.4772496]
processes on the electronic properties of illuminated graphene
nanoribbons. We find that by tuning the device setup (edges geometries,
ribbon width, and polarization direction), a laser with frequency Omega
may either not affect the electronic structure, or induce bandgaps or depletions at +/-(h) over bar Omega=2, and/or at other energies not
commensurate with half the photon energy. Similar features are also
observed in the dc conductance, suggesting the use of the polarization
direction to switch on and off the graphene device. Our results could
guide the design of novel types of optoelectronic nano-devices. (C) 2012
American Institute of Physics. [http://dx.doi.org/10.1063/1.4772496]
Morell, Eric Suarez; Torres, Luis E F Foa
Radiation effects on the electronic properties of bilayer graphene Journal Article
In: Physical Review B, vol. 86, no. 12, pp. 125449, 2012, ISSN: 2469-9950.
@article{ISI:000309268500009,
title = {Radiation effects on the electronic properties of bilayer graphene},
author = {Eric Suarez Morell and Luis E F {Foa Torres}},
doi = {10.1103/PhysRevB.86.125449},
issn = {2469-9950},
year = {2012},
date = {2012-09-01},
journal = {Physical Review B},
volume = {86},
number = {12},
pages = {125449},
abstract = {We report on the effects of laser illumination on the electronic
properties of bilayer graphene. By using Floquet theory combined with
Green's functions, we unveil the appearance of laser-induced gaps not
only at integer multiples of h Omega/2 but also at the Dirac point with
features which are shown to depend strongly on the laser polarization.
Trigonal warping corrections are shown to lead to important corrections
for radiation in the terahertz range, reducing the size of the dynamical
gaps. Furthermore, our analysis of the topological properties at low
energies reveals that, when irradiated with linearly polarized light,
ideal bilayer graphene behaves as a trivial insulator, whereas circular
polarization leads to a nontrivial insulator per valley.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We report on the effects of laser illumination on the electronic
properties of bilayer graphene. By using Floquet theory combined with
Green's functions, we unveil the appearance of laser-induced gaps not
only at integer multiples of h Omega/2 but also at the Dirac point with
features which are shown to depend strongly on the laser polarization.
Trigonal warping corrections are shown to lead to important corrections
for radiation in the terahertz range, reducing the size of the dynamical
gaps. Furthermore, our analysis of the topological properties at low
energies reveals that, when irradiated with linearly polarized light,
ideal bilayer graphene behaves as a trivial insulator, whereas circular
polarization leads to a nontrivial insulator per valley.
properties of bilayer graphene. By using Floquet theory combined with
Green's functions, we unveil the appearance of laser-induced gaps not
only at integer multiples of h Omega/2 but also at the Dirac point with
features which are shown to depend strongly on the laser polarization.
Trigonal warping corrections are shown to lead to important corrections
for radiation in the terahertz range, reducing the size of the dynamical
gaps. Furthermore, our analysis of the topological properties at low
energies reveals that, when irradiated with linearly polarized light,
ideal bilayer graphene behaves as a trivial insulator, whereas circular
polarization leads to a nontrivial insulator per valley.
2011
Torres, Luis E F Foa; Calvo, Hernan L; Rocha, Claudia G; Cuniberti, Gianaurelio
Enhancing single-parameter quantum charge pumping in carbon-based devices Journal Article
In: Applied Physics Letters, vol. 99, no. 9, 2011, ISSN: 0003-6951.
@article{ISI:000294489300027,
title = {Enhancing single-parameter quantum charge pumping in carbon-based devices},
author = {Luis E F {Foa Torres} and Hernan L Calvo and Claudia G Rocha and Gianaurelio Cuniberti},
doi = {10.1063/1.3630025},
issn = {0003-6951},
year = {2011},
date = {2011-08-01},
journal = {Applied Physics Letters},
volume = {99},
number = {9},
abstract = {We present a theoretical study of quantum charge pumping with a single
ac gate applied to graphene nanoribbons and carbon nanotubes operating
with low resistance contacts. By combining Floquet theory with Green's
function formalism, we show that the pumped current can be tuned and
enhanced by up to two orders of magnitude by an appropriate choice of
device length, gate voltage intensity, and driving frequency and
amplitude. These results offer a promising alternative for enhancing the
pumped currents in these carbon-based devices. (C) 2011 American
Institute of Physics. [doi:10.1063/1.3630025]},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We present a theoretical study of quantum charge pumping with a single
ac gate applied to graphene nanoribbons and carbon nanotubes operating
with low resistance contacts. By combining Floquet theory with Green's
function formalism, we show that the pumped current can be tuned and
enhanced by up to two orders of magnitude by an appropriate choice of
device length, gate voltage intensity, and driving frequency and
amplitude. These results offer a promising alternative for enhancing the
pumped currents in these carbon-based devices. (C) 2011 American
Institute of Physics. [doi:10.1063/1.3630025]
ac gate applied to graphene nanoribbons and carbon nanotubes operating
with low resistance contacts. By combining Floquet theory with Green's
function formalism, we show that the pumped current can be tuned and
enhanced by up to two orders of magnitude by an appropriate choice of
device length, gate voltage intensity, and driving frequency and
amplitude. These results offer a promising alternative for enhancing the
pumped currents in these carbon-based devices. (C) 2011 American
Institute of Physics. [doi:10.1063/1.3630025]
Calvo, Hernan L; Pastawski, Horacio M; Roche, Stephan; Torres, Luis E F Foa
Tuning laser-induced band gaps in graphene Journal Article
In: Applied Physics Letters, vol. 98, no. 23, pp. 092102, 2011, ISSN: 0003-6951.
@article{ISI:000291658900028,
title = {Tuning laser-induced band gaps in graphene},
author = {Hernan L Calvo and Horacio M Pastawski and Stephan Roche and Luis E F Foa Torres},
url = {https://arxiv.org/abs/1105.2327},
doi = {10.1063/1.3597412},
issn = {0003-6951},
year = {2011},
date = {2011-06-01},
journal = {Applied Physics Letters},
volume = {98},
number = {23},
pages = {092102},
abstract = {Could a laser field lead to the much sought-after tunable band gaps in
graphene? By using Floquet theory combined with Green's functions
techniques, we predict that a laser field in the mid-infrared range can
produce observable band gaps in the electronic structure of graphene.
Furthermore, we show how they can be tuned by using the laser
polarization. Our results could serve as a guidance to design
optoelectronic nanodevices. (c) 2011 American Institute of Physics.
[doi:10.1063/1.3597412]},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Could a laser field lead to the much sought-after tunable band gaps in
graphene? By using Floquet theory combined with Green's functions
techniques, we predict that a laser field in the mid-infrared range can
produce observable band gaps in the electronic structure of graphene.
Furthermore, we show how they can be tuned by using the laser
polarization. Our results could serve as a guidance to design
optoelectronic nanodevices. (c) 2011 American Institute of Physics.
[doi:10.1063/1.3597412]
graphene? By using Floquet theory combined with Green's functions
techniques, we predict that a laser field in the mid-infrared range can
produce observable band gaps in the electronic structure of graphene.
Furthermore, we show how they can be tuned by using the laser
polarization. Our results could serve as a guidance to design
optoelectronic nanodevices. (c) 2011 American Institute of Physics.
[doi:10.1063/1.3597412]
Rocha, C G; Pacheco, M; Torres, L E F Foa; Cuniberti, G; Latge, A
Transport response of carbon-based resonant cavities under time-dependent potential and magnetic fields Journal Article
In: EPL, vol. 94, no. 4, pp. 47002, 2011, ISSN: 0295-5075.
@article{ISI:000290718900020,
title = {Transport response of carbon-based resonant cavities under time-dependent potential and magnetic fields},
author = {C G Rocha and M Pacheco and L E F {Foa Torres} and G Cuniberti and A Latge},
doi = {10.1209/0295-5075/94/47002},
issn = {0295-5075},
year = {2011},
date = {2011-05-01},
journal = {EPL},
volume = {94},
number = {4},
pages = {47002},
abstract = {Here we report theoretical transport calculations on carbon-based
nanoMaterials used as resonator cavities under the effects of a
time-dependent field. A magnetic field is considered as an extra
modulator tool, able to encode binary ON or OFF transmission states on
the quantum systems. Regular either complex conductance Fabry-Perot
patterns mapped onto gate vs. bias voltage diagrams can be revealed
depending on the set of parameters used on the simulations (amplitude
and frequency of the ac field and magnetic-field intensity). We discuss
the interplay between the effects on the resonant cavity conductance,
caused by the presence of an ac gate plate, which tends to delocalize
the electronic wave functions, and an external magnetic field that
oppositely localizes the electrons. Copyright (C) EPLA, 2011},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Here we report theoretical transport calculations on carbon-based
nanoMaterials used as resonator cavities under the effects of a
time-dependent field. A magnetic field is considered as an extra
modulator tool, able to encode binary ON or OFF transmission states on
the quantum systems. Regular either complex conductance Fabry-Perot
patterns mapped onto gate vs. bias voltage diagrams can be revealed
depending on the set of parameters used on the simulations (amplitude
and frequency of the ac field and magnetic-field intensity). We discuss
the interplay between the effects on the resonant cavity conductance,
caused by the presence of an ac gate plate, which tends to delocalize
the electronic wave functions, and an external magnetic field that
oppositely localizes the electrons. Copyright (C) EPLA, 2011
nanoMaterials used as resonator cavities under the effects of a
time-dependent field. A magnetic field is considered as an extra
modulator tool, able to encode binary ON or OFF transmission states on
the quantum systems. Regular either complex conductance Fabry-Perot
patterns mapped onto gate vs. bias voltage diagrams can be revealed
depending on the set of parameters used on the simulations (amplitude
and frequency of the ac field and magnetic-field intensity). We discuss
the interplay between the effects on the resonant cavity conductance,
caused by the presence of an ac gate plate, which tends to delocalize
the electronic wave functions, and an external magnetic field that
oppositely localizes the electrons. Copyright (C) EPLA, 2011
2010
Poetschke, M; Rocha, C G; Torres, L E F Foa; Roche, S; Cuniberti, G
Modeling graphene-based nanoelectromechanical devices Journal Article
In: Physical Review B, vol. 81, no. 19, pp. 115435, 2010, ISSN: 2469-9950.
@article{ISI:000278142000014,
title = {Modeling graphene-based nanoelectromechanical devices},
author = {M Poetschke and C G Rocha and L E F {Foa Torres} and S Roche and G Cuniberti},
doi = {10.1103/PhysRevB.81.193404},
issn = {2469-9950},
year = {2010},
date = {2010-05-01},
journal = {Physical Review B},
volume = {81},
number = {19},
pages = {115435},
abstract = {We report on a theoretical study of charge transport properties of
graphene nanoribbons under external mechanical stress. The influence of
mechanical forces on the ribbon conductance is shown to be strongly
dependent on the ribbon edge symmetry, i.e., zigzag versus armchair. In
contrast to zigzag-edge nanoribbons which remain robust against high
strain deformations, a stretching-induced metal-semiconductor transition
is obtained for armchair-edge configurations. Our results point out that
armchair edge ribbons are consequently much better suited for
electromechanical applications.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We report on a theoretical study of charge transport properties of
graphene nanoribbons under external mechanical stress. The influence of
mechanical forces on the ribbon conductance is shown to be strongly
dependent on the ribbon edge symmetry, i.e., zigzag versus armchair. In
contrast to zigzag-edge nanoribbons which remain robust against high
strain deformations, a stretching-induced metal-semiconductor transition
is obtained for armchair-edge configurations. Our results point out that
armchair edge ribbons are consequently much better suited for
electromechanical applications.
graphene nanoribbons under external mechanical stress. The influence of
mechanical forces on the ribbon conductance is shown to be strongly
dependent on the ribbon edge symmetry, i.e., zigzag versus armchair. In
contrast to zigzag-edge nanoribbons which remain robust against high
strain deformations, a stretching-induced metal-semiconductor transition
is obtained for armchair-edge configurations. Our results point out that
armchair edge ribbons are consequently much better suited for
electromechanical applications.
Rocha, Claudia G; Torres, Luis E F Foa; Cuniberti, Gianaurelio
ac transport in graphene-based Fabry-Peacuterot devices Journal Article
In: Physical Review B, vol. 81, no. 11, pp. 115435, 2010, ISSN: 2469-9950.
@article{ISI:000276248800148,
title = {ac transport in graphene-based Fabry-Peacuterot devices},
author = {Claudia G Rocha and Luis E F {Foa Torres} and Gianaurelio Cuniberti},
doi = {10.1103/PhysRevB.81.115435},
issn = {2469-9950},
year = {2010},
date = {2010-03-01},
journal = {Physical Review B},
volume = {81},
number = {11},
pages = {115435},
abstract = {We report on a theoretical study of the effects of time-dependent fields
on electronic transport through graphene nanoribbon devices. The
Fabry-Peacuterot interference pattern is modified by an ac gating in a
way that depends strongly on the shape of the graphene edges. While for
armchair edges the patterns are found to be regular and can be
controlled very efficiently by tuning the ac field, samples with zigzag
edges exhibit a much more complex interference pattern due to their
peculiar electronic structure. These studies highlight the main role
played by geometric details of graphene nanoribbons within the coherent
transport regime. We also extend our analysis to noise power response
identifying under which conditions it is possible to minimize the
current fluctuations as well as exploring scaling properties of noise
with the length and width of the systems.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We report on a theoretical study of the effects of time-dependent fields
on electronic transport through graphene nanoribbon devices. The
Fabry-Peacuterot interference pattern is modified by an ac gating in a
way that depends strongly on the shape of the graphene edges. While for
armchair edges the patterns are found to be regular and can be
controlled very efficiently by tuning the ac field, samples with zigzag
edges exhibit a much more complex interference pattern due to their
peculiar electronic structure. These studies highlight the main role
played by geometric details of graphene nanoribbons within the coherent
transport regime. We also extend our analysis to noise power response
identifying under which conditions it is possible to minimize the
current fluctuations as well as exploring scaling properties of noise
with the length and width of the systems.
on electronic transport through graphene nanoribbon devices. The
Fabry-Peacuterot interference pattern is modified by an ac gating in a
way that depends strongly on the shape of the graphene edges. While for
armchair edges the patterns are found to be regular and can be
controlled very efficiently by tuning the ac field, samples with zigzag
edges exhibit a much more complex interference pattern due to their
peculiar electronic structure. These studies highlight the main role
played by geometric details of graphene nanoribbons within the coherent
transport regime. We also extend our analysis to noise power response
identifying under which conditions it is possible to minimize the
current fluctuations as well as exploring scaling properties of noise
with the length and width of the systems.
2009
Torres, Luis E F Foa; Cuniberti, G
Controlling the conductance and noise of driven carbon-based Fabry-Perot devices Journal Article
In: Applied Physics Letters, vol. 94, no. 22, pp. 222103, 2009, ISSN: 0003-6951.
@article{ISI:000266674300026,
title = {Controlling the conductance and noise of driven carbon-based Fabry-Perot devices},
author = {Luis E F {Foa Torres} and G Cuniberti},
doi = {10.1063/1.3147865},
issn = {0003-6951},
year = {2009},
date = {2009-06-01},
journal = {Applied Physics Letters},
volume = {94},
number = {22},
pages = {222103},
abstract = {We report on ac transport through carbon nanotube Fabry-Perot devices.
We show that tuning the intensity of the ac gating induces an
alternation of suppression and partial revival of the conductance
interference pattern. For frequencies matching integer multiples of the
level spacing of the system Delta, the conductance remains irresponsive
to the external field. In contrast, the noise in the low bias voltage
limit behaves as in the static case only when the frequency matches an
even multiple of the level spacing, thereby highlighting its phase
sensitivity in a manifestation of the wagon-wheel effect in the quantum
domain.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We report on ac transport through carbon nanotube Fabry-Perot devices.
We show that tuning the intensity of the ac gating induces an
alternation of suppression and partial revival of the conductance
interference pattern. For frequencies matching integer multiples of the
level spacing of the system Delta, the conductance remains irresponsive
to the external field. In contrast, the noise in the low bias voltage
limit behaves as in the static case only when the frequency matches an
even multiple of the level spacing, thereby highlighting its phase
sensitivity in a manifestation of the wagon-wheel effect in the quantum
domain.
We show that tuning the intensity of the ac gating induces an
alternation of suppression and partial revival of the conductance
interference pattern. For frequencies matching integer multiples of the
level spacing of the system Delta, the conductance remains irresponsive
to the external field. In contrast, the noise in the low bias voltage
limit behaves as in the static case only when the frequency matches an
even multiple of the level spacing, thereby highlighting its phase
sensitivity in a manifestation of the wagon-wheel effect in the quantum
domain.
Torres, L E F Foa; Cuniberti, G
AC transport in carbon-based devices: challenges and perspectives Journal Article
In: COMPTES RENDUS PHYSIQUE, vol. 10, no. 4, pp. 297-304, 2009, ISSN: 1631-0705.
@article{ISI:000268471600005,
title = {AC transport in carbon-based devices: challenges and perspectives},
author = {L E F {Foa Torres} and G Cuniberti},
doi = {10.1016/j.crhy.2009.05.003},
issn = {1631-0705},
year = {2009},
date = {2009-05-01},
journal = {COMPTES RENDUS PHYSIQUE},
volume = {10},
number = {4},
pages = {297-304},
abstract = {Time-dependent fields are a valuable tool to control fundamental quantum
phenomena in highly coherent low dimensional electron systems. Carbon
nanotubes and graphene are a promising ground for these studies. Here we
offer a brief overview of driven electronic transport in carbon-based
Materials with the main focus on carbon nanotubes. Recent results
predicting control of the current and noise in nanotube based
Fabry-Perot devices are highlighted. To cite this article: LEX Foa
Torres, G. Cuniberti, C. R. Physique 10 (2009). (C) 2009 Academie des
sciences. Published by Elsevier Masson SAS. All rights reserved.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Time-dependent fields are a valuable tool to control fundamental quantum
phenomena in highly coherent low dimensional electron systems. Carbon
nanotubes and graphene are a promising ground for these studies. Here we
offer a brief overview of driven electronic transport in carbon-based
Materials with the main focus on carbon nanotubes. Recent results
predicting control of the current and noise in nanotube based
Fabry-Perot devices are highlighted. To cite this article: LEX Foa
Torres, G. Cuniberti, C. R. Physique 10 (2009). (C) 2009 Academie des
sciences. Published by Elsevier Masson SAS. All rights reserved.
phenomena in highly coherent low dimensional electron systems. Carbon
nanotubes and graphene are a promising ground for these studies. Here we
offer a brief overview of driven electronic transport in carbon-based
Materials with the main focus on carbon nanotubes. Recent results
predicting control of the current and noise in nanotube based
Fabry-Perot devices are highlighted. To cite this article: LEX Foa
Torres, G. Cuniberti, C. R. Physique 10 (2009). (C) 2009 Academie des
sciences. Published by Elsevier Masson SAS. All rights reserved.
2008
Torres, Luis E F Foa; Avriller, Remi; Roche, Stephan
Nonequilibrium energy gaps in carbon nanotubes: Role of phonon symmetries Journal Article
In: Physical Review B, vol. 78, no. 3, pp. 035412, 2008, ISSN: 2469-9950.
@article{ISI:000258190300128,
title = {Nonequilibrium energy gaps in carbon nanotubes: Role of phonon symmetries},
author = {Luis E F {Foa Torres} and Remi Avriller and Stephan Roche},
doi = {10.1103/PhysRevB.78.035412},
issn = {2469-9950},
year = {2008},
date = {2008-07-01},
journal = {Physical Review B},
volume = {78},
number = {3},
pages = {035412},
abstract = {We report on a theoretical study of inelastic backscattering processes
and quantum transport in metallic carbon nanotubes. The consequences of
a Peierls-like mechanism due to e-ph interaction with optic phonons in
the transport properties is explored. The occurrence of nonequilibrium
energy gaps driven by an applied bias voltage is derived from a
nonperturbative treatment of electron-phonon coupling with longitudinal
optic as well as K A(1)' modes. The case of armchair tubes is explicitly
considered, and further generalizations to tubes of arbitrary helicity
are outlined.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We report on a theoretical study of inelastic backscattering processes
and quantum transport in metallic carbon nanotubes. The consequences of
a Peierls-like mechanism due to e-ph interaction with optic phonons in
the transport properties is explored. The occurrence of nonequilibrium
energy gaps driven by an applied bias voltage is derived from a
nonperturbative treatment of electron-phonon coupling with longitudinal
optic as well as K A(1)' modes. The case of armchair tubes is explicitly
considered, and further generalizations to tubes of arbitrary helicity
are outlined.
and quantum transport in metallic carbon nanotubes. The consequences of
a Peierls-like mechanism due to e-ph interaction with optic phonons in
the transport properties is explored. The occurrence of nonequilibrium
energy gaps driven by an applied bias voltage is derived from a
nonperturbative treatment of electron-phonon coupling with longitudinal
optic as well as K A(1)' modes. The case of armchair tubes is explicitly
considered, and further generalizations to tubes of arbitrary helicity
are outlined.
Coiffic, J C; Torres, L E Foa; Poche, Le H; Fayolle, M; Roche, S; Maitrejean, S; Roualdes, S; Ayral, A
An application of carbon nanotubes for integrated circuit interconnects Journal Article
In: Carbon Nanotubes and Associated Devices, vol. 7037, pp. 70370D, 2008.
@article{coiffic_application_2008,
title = {An application of carbon nanotubes for integrated circuit interconnects},
author = {J C Coiffic and L E {Foa Torres} and Le H Poche and M Fayolle and S Roche and S Maitrejean and S Roualdes and A Ayral},
url = {https://www.spiedigitallibrary.org/conference-proceedings-of-spie/7037/70370D/An-application-of-carbon-nanotubes-for-integrated-circuit-interconnects/10.1117/12.799100.short},
doi = {10.1117/12.799100},
year = {2008},
date = {2008-01-01},
urldate = {2020-08-08},
journal = {Carbon Nanotubes and Associated Devices},
volume = {7037},
pages = {70370D},
abstract = {Integrated circuits fabrication is soon reaching strong limitations. Help could come from using carbon nanotubes as conducting wires for interconnects. Although this solution was proposed six years ago, researchers still come up with many obstacles such as localization, low temperature growth on copper, contacting and reproducibility. The integration processes exposed here intend to meet the industrial requirements. Two approaches are then possibly followed. Either using densely packed single wall (SWCNT) (or very tiny multiwall) nanotubes, or filling up the whole interconnect diameter with a single large multiwall (MWCNT) nanotube. In this work, we focus on the integration of multiwall vertical interconnects. Densely packed MWCNTs are grown in via holes by CVD. Alternatively, we have developed a method to obtain a single large nanofibre grown by PECVD (MWCNF) in each via hole. Electrical measurements are performed on CVD and PECVD grown carbon nanotubes. The role of electron-phonon interaction in these devices is also briefly discussed.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Integrated circuits fabrication is soon reaching strong limitations. Help could come from using carbon nanotubes as conducting wires for interconnects. Although this solution was proposed six years ago, researchers still come up with many obstacles such as localization, low temperature growth on copper, contacting and reproducibility. The integration processes exposed here intend to meet the industrial requirements. Two approaches are then possibly followed. Either using densely packed single wall (SWCNT) (or very tiny multiwall) nanotubes, or filling up the whole interconnect diameter with a single large multiwall (MWCNT) nanotube. In this work, we focus on the integration of multiwall vertical interconnects. Densely packed MWCNTs are grown in via holes by CVD. Alternatively, we have developed a method to obtain a single large nanofibre grown by PECVD (MWCNF) in each via hole. Electrical measurements are performed on CVD and PECVD grown carbon nanotubes. The role of electron-phonon interaction in these devices is also briefly discussed.
2007
Coiffic, J C; Fayolle, M; Maitrejean, S; Torres, L E F Foa; Poche, H Le
Conduction regime in innovative carbon nanotube via interconnect architectures Journal Article
In: Applied Physics Letters, vol. 91, no. 25, 2007, ISSN: 0003-6951.
@article{ISI:000251908100044,
title = {Conduction regime in innovative carbon nanotube via interconnect architectures},
author = {J C Coiffic and M Fayolle and S Maitrejean and L E F {Foa Torres} and H Le Poche},
doi = {10.1063/1.2826274},
issn = {0003-6951},
year = {2007},
date = {2007-12-01},
journal = {Applied Physics Letters},
volume = {91},
number = {25},
abstract = {We report on the electrical properties of multiwall carbon nanotube
based via interconnects over a broad range of temperature and bias
voltage. By using innovating processing techniques, high density
nanotube vias have been fabricated from single damascene and double
damascene via architectures with diameters down to 140 nm. For single
damascene structures, resistances as low as 20 Omega have been achieved
for 300 nm via size. Further measurements show that the conductance
increases with temperature following an exponential law, which can be
interpreted in terms of a disordered quasi-one dimensional conduction
regime. (c) 2007 American Institute of Physics.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We report on the electrical properties of multiwall carbon nanotube
based via interconnects over a broad range of temperature and bias
voltage. By using innovating processing techniques, high density
nanotube vias have been fabricated from single damascene and double
damascene via architectures with diameters down to 140 nm. For single
damascene structures, resistances as low as 20 Omega have been achieved
for 300 nm via size. Further measurements show that the conductance
increases with temperature following an exponential law, which can be
interpreted in terms of a disordered quasi-one dimensional conduction
regime. (c) 2007 American Institute of Physics.
based via interconnects over a broad range of temperature and bias
voltage. By using innovating processing techniques, high density
nanotube vias have been fabricated from single damascene and double
damascene via architectures with diameters down to 140 nm. For single
damascene structures, resistances as low as 20 Omega have been achieved
for 300 nm via size. Further measurements show that the conductance
increases with temperature following an exponential law, which can be
interpreted in terms of a disordered quasi-one dimensional conduction
regime. (c) 2007 American Institute of Physics.
Roche, Stephan; Jiang, Jie; Torres, Luis E F Foa; Saito, Riichiro
Charge transport in carbon nanotubes: quantum effects of electron-phonon coupling Journal Article
In: Journal of Physics-Condensed Matter, vol. 19, no. 18, pp. 183203, 2007, ISSN: 0953-8984, (Invited Topical Review).
@article{ISI:000246556500006,
title = {Charge transport in carbon nanotubes: quantum effects of electron-phonon coupling},
author = {Stephan Roche and Jie Jiang and Luis E F {Foa Torres} and Riichiro Saito},
doi = {10.1088/0953-8984/19/18/183203},
issn = {0953-8984},
year = {2007},
date = {2007-05-01},
journal = {Journal of Physics-Condensed Matter},
volume = {19},
number = {18},
pages = {183203},
abstract = {This review deals with the role of electron-phonon (e-ph) coupling in
quantum transport of carbon nanotubes. First, the case of low-energy
phonons and weak localization phenomena is addressed, followed by a
summary of inelastic scattering lengths within the Fermi golden rule. A
second part outlines the contribution of high-energy optic phonon modes,
and discusses the applicability limits of semi-classical transport
theory. The computational methodologies used to deepen the
phonon-induced dephasing or inelastic transmission range from the
time-dependent Schrodinger equation and Kubo framework to a novel
many-body treatment of e-ph interaction.},
note = {Invited Topical Review},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
This review deals with the role of electron-phonon (e-ph) coupling in
quantum transport of carbon nanotubes. First, the case of low-energy
phonons and weak localization phenomena is addressed, followed by a
summary of inelastic scattering lengths within the Fermi golden rule. A
second part outlines the contribution of high-energy optic phonon modes,
and discusses the applicability limits of semi-classical transport
theory. The computational methodologies used to deepen the
phonon-induced dephasing or inelastic transmission range from the
time-dependent Schrodinger equation and Kubo framework to a novel
many-body treatment of e-ph interaction.
quantum transport of carbon nanotubes. First, the case of low-energy
phonons and weak localization phenomena is addressed, followed by a
summary of inelastic scattering lengths within the Fermi golden rule. A
second part outlines the contribution of high-energy optic phonon modes,
and discusses the applicability limits of semi-classical transport
theory. The computational methodologies used to deepen the
phonon-induced dephasing or inelastic transmission range from the
time-dependent Schrodinger equation and Kubo framework to a novel
many-body treatment of e-ph interaction.
Torres, Luis E F Foa; Roche, Stephan
Diameter dependent phonon-induced backscattering in semiconducting carbon nanotubes Journal Article
In: Physical Review B, vol. 75, no. 15, pp. 153402, 2007, ISSN: 2469-9950.
@article{ISI:000246075300024,
title = {Diameter dependent phonon-induced backscattering in semiconducting carbon nanotubes},
author = {Luis E F {Foa Torres} and Stephan Roche},
doi = {10.1103/PhysRevB.75.153402},
issn = {2469-9950},
year = {2007},
date = {2007-04-01},
journal = {Physical Review B},
volume = {75},
number = {15},
pages = {153402},
abstract = {We report on a many-body theoretical study of the effects of
electron-(optical)phonon interaction on transport through zigzag
semiconducting carbon nanotubes. We show that the interaction with
A(1)(L) phonon mode of energy h omega(0) induces the opening of
nonequilibrium energy gaps at h omega(0)/2 and/or h omega(0) above
(below) the charge neutrality point, depending on the tube diameter and
phonon population. These mechanisms, which correspond to inelastic
backscattering with phonon emission (absorption), are beyond the scope
of the conventional Born-Oppenheimer and Fermi golden rule
approximations.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We report on a many-body theoretical study of the effects of
electron-(optical)phonon interaction on transport through zigzag
semiconducting carbon nanotubes. We show that the interaction with
A(1)(L) phonon mode of energy h omega(0) induces the opening of
nonequilibrium energy gaps at h omega(0)/2 and/or h omega(0) above
(below) the charge neutrality point, depending on the tube diameter and
phonon population. These mechanisms, which correspond to inelastic
backscattering with phonon emission (absorption), are beyond the scope
of the conventional Born-Oppenheimer and Fermi golden rule
approximations.
electron-(optical)phonon interaction on transport through zigzag
semiconducting carbon nanotubes. We show that the interaction with
A(1)(L) phonon mode of energy h omega(0) induces the opening of
nonequilibrium energy gaps at h omega(0)/2 and/or h omega(0) above
(below) the charge neutrality point, depending on the tube diameter and
phonon population. These mechanisms, which correspond to inelastic
backscattering with phonon emission (absorption), are beyond the scope
of the conventional Born-Oppenheimer and Fermi golden rule
approximations.
Torres, L E F Foa; Roche, S
Electron-phonon induced conductance gaps in carbon nanotubes Journal Article
In: Applied Physics A-Materials Science & Processing, vol. 86, no. 3, pp. 283-288, 2007, ISSN: 0947-8396.
@article{ISI:000243396200002,
title = {Electron-phonon induced conductance gaps in carbon nanotubes},
author = {L E F {Foa Torres} and S Roche},
doi = {10.1007/s00339-006-3760-4},
issn = {0947-8396},
year = {2007},
date = {2007-03-01},
journal = {Applied Physics A-Materials Science \& Processing},
volume = {86},
number = {3},
pages = {283-288},
abstract = {This work presents a theoretical study of quantum charge transport
through zigzag and armchair carbon nanotubes in the presence of electron
- phonon interaction. By using a non-perturbative description of the
electron - phonon coupling in Fock space, one reveals the occurrence of
a transmission gap opening at half the optical A(1)( L) phonon energy,
(H) over bar omega(0)/2, above ( below) the charge neutrality point
associated with phonon emission ( absorption). This mechanism, which is
prevented at low bias voltages by Pauli blocking, develops when the
system is driven out of equilibrium ( high bias voltages). This yields
an onset of current saturation of about 30 mu A, which brings a
completely novel perspective to understand electrical characteristics of
nanotube-based devices.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
This work presents a theoretical study of quantum charge transport
through zigzag and armchair carbon nanotubes in the presence of electron
- phonon interaction. By using a non-perturbative description of the
electron - phonon coupling in Fock space, one reveals the occurrence of
a transmission gap opening at half the optical A(1)( L) phonon energy,
(H) over bar omega(0)/2, above ( below) the charge neutrality point
associated with phonon emission ( absorption). This mechanism, which is
prevented at low bias voltages by Pauli blocking, develops when the
system is driven out of equilibrium ( high bias voltages). This yields
an onset of current saturation of about 30 mu A, which brings a
completely novel perspective to understand electrical characteristics of
nanotube-based devices.
through zigzag and armchair carbon nanotubes in the presence of electron
- phonon interaction. By using a non-perturbative description of the
electron - phonon coupling in Fock space, one reveals the occurrence of
a transmission gap opening at half the optical A(1)( L) phonon energy,
(H) over bar omega(0)/2, above ( below) the charge neutrality point
associated with phonon emission ( absorption). This mechanism, which is
prevented at low bias voltages by Pauli blocking, develops when the
system is driven out of equilibrium ( high bias voltages). This yields
an onset of current saturation of about 30 mu A, which brings a
completely novel perspective to understand electrical characteristics of
nanotube-based devices.
Pastawski, H M; Danieli, E P; Calvo, H L; Torres, L E F Foa
Towards a time reversal mirror for quantum systems Journal Article
In: EPL, vol. 77, no. 4, pp. 40001, 2007, ISSN: 0295-5075.
@article{ISI:000245743300001,
title = {Towards a time reversal mirror for quantum systems},
author = {H M Pastawski and E P Danieli and H L Calvo and L E F {Foa Torres}},
doi = {10.1209/0295-5075/77/40001},
issn = {0295-5075},
year = {2007},
date = {2007-01-01},
journal = {EPL},
volume = {77},
number = {4},
pages = {40001},
abstract = {The reversion of the time evolution of a quantum state can be achieved
by changing the sign of the Hamiltonian as in the Loschmidt echo and
polarization echo experiment in NMR. In this work we describe an
alternative mechanism inspired by the acoustic time reversal mirror. By
solving the inverse time problem in a discrete space we develop a new
procedure, the perfect inverse filter. It achieves the exact time
reversion in a given region by reinjecting a prescribed wave function at
the region's boundary. Copyright (C) EPLA, 2007.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The reversion of the time evolution of a quantum state can be achieved
by changing the sign of the Hamiltonian as in the Loschmidt echo and
polarization echo experiment in NMR. In this work we describe an
alternative mechanism inspired by the acoustic time reversal mirror. By
solving the inverse time problem in a discrete space we develop a new
procedure, the perfect inverse filter. It achieves the exact time
reversion in a given region by reinjecting a prescribed wave function at
the region's boundary. Copyright (C) EPLA, 2007.
by changing the sign of the Hamiltonian as in the Loschmidt echo and
polarization echo experiment in NMR. In this work we describe an
alternative mechanism inspired by the acoustic time reversal mirror. By
solving the inverse time problem in a discrete space we develop a new
procedure, the perfect inverse filter. It achieves the exact time
reversion in a given region by reinjecting a prescribed wave function at
the region's boundary. Copyright (C) EPLA, 2007.
Torres, L E F Foa; Roche, S
Effects of electron-phonon interaction on transport through carbon nanotubes: lifting of degeneracies in Fock-space Journal Article
In: Journal of Physics: Conference Series, vol. 92, pp. 012057, 2007, ISSN: 1742-6596.
@article{torres_effects_2007,
title = {Effects of electron-phonon interaction on transport through carbon nanotubes: lifting of degeneracies in Fock-space},
author = {L E F {Foa Torres} and S Roche},
url = {https://doi.org/10.1088%2F1742-6596%2F92%2F1%2F012057},
doi = {10.1088/1742-6596/92/1/012057},
issn = {1742-6596},
year = {2007},
date = {2007-01-01},
urldate = {2020-08-08},
journal = {Journal of Physics: Conference Series},
volume = {92},
pages = {012057},
abstract = {In this contribution we present a brief overview of recent results about the effects of electron-phonon interaction in electronic transport through metallic single-walled carbon nanotubes. In particular, we present an electron-phonon-induced backscattering mechanism which can be seen as the removal of degeneracies in the electron-phonon Fock space. This mechanism, which is activated when driving the system out of equilibrium, is beyond the scope of commonly used mean field approaches. Possible experimental consequences of such phenomenon are also discussed.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
In this contribution we present a brief overview of recent results about the effects of electron-phonon interaction in electronic transport through metallic single-walled carbon nanotubes. In particular, we present an electron-phonon-induced backscattering mechanism which can be seen as the removal of degeneracies in the electron-phonon Fock space. This mechanism, which is activated when driving the system out of equilibrium, is beyond the scope of commonly used mean field approaches. Possible experimental consequences of such phenomenon are also discussed.
2006
Torres, Luis E F Foa; Roche, Stephan
Inelastic quantum transport and peierls-like mechanism in carbon nanotubes Journal Article
In: Physical Review Letters, vol. 97, no. 7, pp. 076804, 2006, ISSN: 0031-9007.
@article{ISI:000239842100050,
title = {Inelastic quantum transport and peierls-like mechanism in carbon nanotubes},
author = {Luis E F {Foa Torres} and Stephan Roche},
doi = {10.1103/PhysRevLett.97.076804},
issn = {0031-9007},
year = {2006},
date = {2006-08-01},
journal = {Physical Review Letters},
volume = {97},
number = {7},
pages = {076804},
abstract = {We report on a theoretical study of inelastic quantum transport in
(3m,0) carbon nanotubes. By using a many-body description of the
electron-phonon interaction in Fock space, a novel mechanism involving
optical phonon emission (absorption) is shown to induce an unprecedented
energy-gap opening at half the phonon energy, h omega(0)/2, above
(below) the charge neutrality point. This mechanism, which is prevented
by Pauli blocking at low bias voltages, is activated at bias voltages on
the order of h omega(0).},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We report on a theoretical study of inelastic quantum transport in
(3m,0) carbon nanotubes. By using a many-body description of the
electron-phonon interaction in Fock space, a novel mechanism involving
optical phonon emission (absorption) is shown to induce an unprecedented
energy-gap opening at half the phonon energy, h omega(0)/2, above
(below) the charge neutrality point. This mechanism, which is prevented
by Pauli blocking at low bias voltages, is activated at bias voltages on
the order of h omega(0).
(3m,0) carbon nanotubes. By using a many-body description of the
electron-phonon interaction in Fock space, a novel mechanism involving
optical phonon emission (absorption) is shown to induce an unprecedented
energy-gap opening at half the phonon energy, h omega(0)/2, above
(below) the charge neutrality point. This mechanism, which is prevented
by Pauli blocking at low bias voltages, is activated at bias voltages on
the order of h omega(0).
Torres, L E F Foa; Pastawski, H M; Medina, E
Antiresonances as precursors of decoherence Journal Article
In: Europhysics Letters, vol. 73, no. 2, pp. 164-170, 2006, ISSN: 0295-5075.
@article{ISI:000234447700002,
title = {Antiresonances as precursors of decoherence},
author = {L E F {Foa Torres} and H M Pastawski and E Medina},
doi = {10.1209/epl/i2005-10374-9},
issn = {0295-5075},
year = {2006},
date = {2006-01-01},
journal = {Europhysics Letters},
volume = {73},
number = {2},
pages = {164-170},
abstract = {We show that, in the presence of a complex spectrum, antiresonances act
as a precursor for dephasing enabling the crossover to a fully
decoherent transport even within a unitary Hamiltonian description. This
general scenario is illustrated here by focusing on a quantum dot
coupled to a chaotic cavity containing a finite, but large, number of
states using a Hamiltonian formulation. For weak coupling to a chaotic
cavity with a sufficiently dense spectrum, the ensuing complex structure
of resonances and antiresonances leads to phase randomization under
coarse graining in energy. Such phase instabilities and coarse graining
are the ingredients for a mechanism producing decoherence and thus
irreversibility. For the present simple model one finds a conductance
that coincides with the one obtained by adding a ficticious voltage
probe within the Landauer-Buttiker picture. This sheds new light on how
the microscopic mechanisms that produce phase fluctuations induce
decoherence.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We show that, in the presence of a complex spectrum, antiresonances act
as a precursor for dephasing enabling the crossover to a fully
decoherent transport even within a unitary Hamiltonian description. This
general scenario is illustrated here by focusing on a quantum dot
coupled to a chaotic cavity containing a finite, but large, number of
states using a Hamiltonian formulation. For weak coupling to a chaotic
cavity with a sufficiently dense spectrum, the ensuing complex structure
of resonances and antiresonances leads to phase randomization under
coarse graining in energy. Such phase instabilities and coarse graining
are the ingredients for a mechanism producing decoherence and thus
irreversibility. For the present simple model one finds a conductance
that coincides with the one obtained by adding a ficticious voltage
probe within the Landauer-Buttiker picture. This sheds new light on how
the microscopic mechanisms that produce phase fluctuations induce
decoherence.
as a precursor for dephasing enabling the crossover to a fully
decoherent transport even within a unitary Hamiltonian description. This
general scenario is illustrated here by focusing on a quantum dot
coupled to a chaotic cavity containing a finite, but large, number of
states using a Hamiltonian formulation. For weak coupling to a chaotic
cavity with a sufficiently dense spectrum, the ensuing complex structure
of resonances and antiresonances leads to phase randomization under
coarse graining in energy. Such phase instabilities and coarse graining
are the ingredients for a mechanism producing decoherence and thus
irreversibility. For the present simple model one finds a conductance
that coincides with the one obtained by adding a ficticious voltage
probe within the Landauer-Buttiker picture. This sheds new light on how
the microscopic mechanisms that produce phase fluctuations induce
decoherence.
2005
Torres, L E F Foa
Mono-parametric quantum charge pumping: Interplay between spatial interference and photon-assisted tunneling Journal Article
In: Physical Review B, vol. 72, no. 24, pp. 245339, 2005, ISSN: 2469-9950.
@article{ISI:000234342900083,
title = {Mono-parametric quantum charge pumping: Interplay between spatial interference and photon-assisted tunneling},
author = {L E F {Foa Torres}},
doi = {10.1103/PhysRevB.72.245339},
issn = {2469-9950},
year = {2005},
date = {2005-12-01},
journal = {Physical Review B},
volume = {72},
number = {24},
pages = {245339},
abstract = {We analyze quantum charge pumping in an open ring with a dot embedded in
one of its arms. We show that cyclic driving of the dot levels by a
single parameter leads to a pumped current when a static magnetic flux
is simultaneously applied to the ring. Based on the computation of the
Floquet-Green's functions, we show that for low driving frequencies
omega(0), the interplay between the spatial interference through the
ring plus photon-assisted tunneling gives an average direct current,
which is proportional to omega(2)(0). The direction of the pumped
current can be reversed by changing the applied magnetic field.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We analyze quantum charge pumping in an open ring with a dot embedded in
one of its arms. We show that cyclic driving of the dot levels by a
single parameter leads to a pumped current when a static magnetic flux
is simultaneously applied to the ring. Based on the computation of the
Floquet-Green's functions, we show that for low driving frequencies
omega(0), the interplay between the spatial interference through the
ring plus photon-assisted tunneling gives an average direct current,
which is proportional to omega(2)(0). The direction of the pumped
current can be reversed by changing the applied magnetic field.
one of its arms. We show that cyclic driving of the dot levels by a
single parameter leads to a pumped current when a static magnetic flux
is simultaneously applied to the ring. Based on the computation of the
Floquet-Green's functions, we show that for low driving frequencies
omega(0), the interplay between the spatial interference through the
ring plus photon-assisted tunneling gives an average direct current,
which is proportional to omega(2)(0). The direction of the pumped
current can be reversed by changing the applied magnetic field.
2004
Torres, L E F Foa; Lewenkopf, C H; Pastawski, H M
Conductance fluctuations in Coulomb-blockaded dots: from the sequential theory to a quantum coherent description Journal Article
In: PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES, vol. 22, no. 1-3, pp. 526-529, 2004, ISSN: 1386-9477, (15th International Conference on Electronic Properties of Two-Dimensional Systems (EP2DS-15), Nara, JAPAN, JUL 14-18, 2003).
@article{ISI:000221140800127,
title = {Conductance fluctuations in Coulomb-blockaded dots: from the sequential
theory to a quantum coherent description},
author = {L E F {Foa Torres} and C H Lewenkopf and H M Pastawski},
doi = {10.1016/j.physe.2003.12.061},
issn = {1386-9477},
year = {2004},
date = {2004-04-01},
journal = {PHYSICA E-LOW-DIMENSIONAL SYSTEMS \& NANOSTRUCTURES},
volume = {22},
number = {1-3},
pages = {526-529},
abstract = {We present a quantum coherent approach to describe electronic transport
through quantum dots in the Coulomb-blockade regime. Our approach
contains the standard sequential theory in the limit of very weak
coupling. We show that our approach explains some puzzles on the
statistics of conductance peak heights raised by recent experiments. (C)
2003 Elsevier B.V. All rights reserved.},
note = {15th International Conference on Electronic Properties of
Two-Dimensional Systems (EP2DS-15), Nara, JAPAN, JUL 14-18, 2003},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We present a quantum coherent approach to describe electronic transport
through quantum dots in the Coulomb-blockade regime. Our approach
contains the standard sequential theory in the limit of very weak
coupling. We show that our approach explains some puzzles on the
statistics of conductance peak heights raised by recent experiments. (C)
2003 Elsevier B.V. All rights reserved.
through quantum dots in the Coulomb-blockade regime. Our approach
contains the standard sequential theory in the limit of very weak
coupling. We show that our approach explains some puzzles on the
statistics of conductance peak heights raised by recent experiments. (C)
2003 Elsevier B.V. All rights reserved.
2003
Torres, L E F Foa; Lewenkopf, C H; Pastawski, H M
Coherent versus sequential electron tunneling in quantum dots Journal Article
In: Physical Review Letters, vol. 91, no. 11, pp. 116801, 2003, ISSN: 0031-9007.
@article{ISI:000185288000045,
title = {Coherent versus sequential electron tunneling in quantum dots},
author = {L E F {Foa Torres} and C H Lewenkopf and H M Pastawski},
doi = {10.1103/PhysRevLett.91.116801},
issn = {0031-9007},
year = {2003},
date = {2003-09-01},
journal = {Physical Review Letters},
volume = {91},
number = {11},
pages = {116801},
abstract = {Manifestations of quantum coherence in the electronic conductance
through nearly closed quantum dots in the Coulomb-blockade regime are
addressed. We show that quantum coherent tunneling processes explain
some puzzling statistical features of the conductance peak heights
observed in recent experiments at low temperatures. We employ the
constant interaction model and the random matrix theory to model the
quantum dot electronic interactions and its single-particle statistical
fluctuations, taking full account of the finite decay width of the
quantum dot levels.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Manifestations of quantum coherence in the electronic conductance
through nearly closed quantum dots in the Coulomb-blockade regime are
addressed. We show that quantum coherent tunneling processes explain
some puzzling statistical features of the conductance peak heights
observed in recent experiments at low temperatures. We employ the
constant interaction model and the random matrix theory to model the
quantum dot electronic interactions and its single-particle statistical
fluctuations, taking full account of the finite decay width of the
quantum dot levels.
through nearly closed quantum dots in the Coulomb-blockade regime are
addressed. We show that quantum coherent tunneling processes explain
some puzzling statistical features of the conductance peak heights
observed in recent experiments at low temperatures. We employ the
constant interaction model and the random matrix theory to model the
quantum dot electronic interactions and its single-particle statistical
fluctuations, taking full account of the finite decay width of the
quantum dot levels.
2002
Pastawski, H M; Torres, L E F Foa; Medina, E
Electron-phonon interaction and electronic decoherence in molecular conductors Journal Article
In: Chemical Physics, vol. 281, no. 2-3, SI, pp. 257-278, 2002, ISSN: 0301-0104.
@article{ISI:000177107000013,
title = {Electron-phonon interaction and electronic decoherence in molecular
conductors},
author = {H M Pastawski and L E F {Foa Torres} and E Medina},
doi = {10.1016/S0301-0104(02)00565-7},
issn = {0301-0104},
year = {2002},
date = {2002-08-01},
journal = {Chemical Physics},
volume = {281},
number = {2-3, SI},
pages = {257-278},
abstract = {We perform a brief but critical review of the Landauer picture of
transport that clarifies how decoherence appears in this approach. On
this basis, we present different models that allow the study of the
coherent and decoherent effects of the interaction with the environment
in the electronic transport. These models are particularly well suited
for the analysis of transport in molecular wires. The effects of
decoherence are described through the D'Amato-Pastawski model that is
explained in detail. We also consider the formation of polarons in some
models for the electron-vibrational interaction. Our quantum coherent
framework allows us to study many-body interference effects. Particular
emphasis is given to the occurrence of anti-resonances as a result of
these interferences. By studying the phase fluctuations in these soluble
models we are able to identify inelastic and decoherence effects. A
brief description of a general formulation for the consideration of
time-dependent transport is also presented. (C) 2002 Elsevier Science
B.V. All rights reserved.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We perform a brief but critical review of the Landauer picture of
transport that clarifies how decoherence appears in this approach. On
this basis, we present different models that allow the study of the
coherent and decoherent effects of the interaction with the environment
in the electronic transport. These models are particularly well suited
for the analysis of transport in molecular wires. The effects of
decoherence are described through the D'Amato-Pastawski model that is
explained in detail. We also consider the formation of polarons in some
models for the electron-vibrational interaction. Our quantum coherent
framework allows us to study many-body interference effects. Particular
emphasis is given to the occurrence of anti-resonances as a result of
these interferences. By studying the phase fluctuations in these soluble
models we are able to identify inelastic and decoherence effects. A
brief description of a general formulation for the consideration of
time-dependent transport is also presented. (C) 2002 Elsevier Science
B.V. All rights reserved.
transport that clarifies how decoherence appears in this approach. On
this basis, we present different models that allow the study of the
coherent and decoherent effects of the interaction with the environment
in the electronic transport. These models are particularly well suited
for the analysis of transport in molecular wires. The effects of
decoherence are described through the D'Amato-Pastawski model that is
explained in detail. We also consider the formation of polarons in some
models for the electron-vibrational interaction. Our quantum coherent
framework allows us to study many-body interference effects. Particular
emphasis is given to the occurrence of anti-resonances as a result of
these interferences. By studying the phase fluctuations in these soluble
models we are able to identify inelastic and decoherence effects. A
brief description of a general formulation for the consideration of
time-dependent transport is also presented. (C) 2002 Elsevier Science
B.V. All rights reserved.
Torres, L E F Foa; Pastawski, H M; Makler, S S
Electron-phonon interaction in electronic tunneling: From sequential rate equations to a coherent description Journal Article
In: Brazilian Journal of Physics, vol. 32, no. 2, pp. 300-302, 2002, ISSN: 0103-9733, (10th Brazillian Workshop on Semiconductor Physics (BWSP 10), GUARUJA, BRAZIL, APR 22-27, 2001).
@article{ISI:000176522000013,
title = {Electron-phonon interaction in electronic tunneling: From sequential rate equations to a coherent description},
author = {L E F {Foa Torres} and H M Pastawski and S S Makler},
issn = {0103-9733},
year = {2002},
date = {2002-06-01},
journal = {Brazilian Journal of Physics},
volume = {32},
number = {2},
pages = {300-302},
abstract = {We discuss the main theoretical approaches for the phonon-assisted
tunneling in double barrier resonant tunneling devices and introduce a
quantum coherent treatment based on the mapping of the many-body problem
into a higher dimensional one-body system. Conditions for a maximized
phonon-emission are established.},
note = {10th Brazillian Workshop on Semiconductor Physics (BWSP 10), GUARUJA,
BRAZIL, APR 22-27, 2001},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We discuss the main theoretical approaches for the phonon-assisted
tunneling in double barrier resonant tunneling devices and introduce a
quantum coherent treatment based on the mapping of the many-body problem
into a higher dimensional one-body system. Conditions for a maximized
phonon-emission are established.
tunneling in double barrier resonant tunneling devices and introduce a
quantum coherent treatment based on the mapping of the many-body problem
into a higher dimensional one-body system. Conditions for a maximized
phonon-emission are established.
Torres, L E F Foa; Pastawski, H M; Makler, S S
An ultrasound emitter based on assisted tunneling Journal Article
In: Solid State Communications, vol. 124, no. 10-11, pp. 363-371, 2002, ISSN: 0038-1098.
@article{ISI:000179595400001,
title = {An ultrasound emitter based on assisted tunneling},
author = {L E F {Foa Torres} and H M Pastawski and S S Makler},
doi = {10.1016/S0038-1098(02)00427-1},
issn = {0038-1098},
year = {2002},
date = {2002-01-01},
journal = {Solid State Communications},
volume = {124},
number = {10-11},
pages = {363-371},
abstract = {The problem of electron tunneling assisted by an elementary excitation
in a double barrier resonant device is usually described within a
sequential (decoherent) approximation. By solving exactly the many-body
problem for a simplified model of electron-phonon interaction we show,
analytically and numerically, that the assisted tunneling peak can be
strongly enhanced by an appropriate election of the geometrical
parameters of the device. This induces a symmetry condition in the Fock
space that maximizes the effectiveness of the scattering process. We
propose that this process could provide the primary longitudinal optical
phonons required to operate a phonon laser (SASER). (C) 2002 Elsevier
Science Ltd. All rights reserved.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The problem of electron tunneling assisted by an elementary excitation
in a double barrier resonant device is usually described within a
sequential (decoherent) approximation. By solving exactly the many-body
problem for a simplified model of electron-phonon interaction we show,
analytically and numerically, that the assisted tunneling peak can be
strongly enhanced by an appropriate election of the geometrical
parameters of the device. This induces a symmetry condition in the Fock
space that maximizes the effectiveness of the scattering process. We
propose that this process could provide the primary longitudinal optical
phonons required to operate a phonon laser (SASER). (C) 2002 Elsevier
Science Ltd. All rights reserved.
in a double barrier resonant device is usually described within a
sequential (decoherent) approximation. By solving exactly the many-body
problem for a simplified model of electron-phonon interaction we show,
analytically and numerically, that the assisted tunneling peak can be
strongly enhanced by an appropriate election of the geometrical
parameters of the device. This induces a symmetry condition in the Fock
space that maximizes the effectiveness of the scattering process. We
propose that this process could provide the primary longitudinal optical
phonons required to operate a phonon laser (SASER). (C) 2002 Elsevier
Science Ltd. All rights reserved.
2001
Torres, L E F Foa; Pastawski, H M; Makler, S S
Tuning a resonance in Fock space: Optimization of phonon emission in a resonant-tunneling device Journal Article
In: Physical Review B, vol. 64, no. 19, pp. 193304, 2001, ISSN: 2469-9950.
@article{ISI:000172307900009,
title = {Tuning a resonance in Fock space: Optimization of phonon emission in a resonant-tunneling device},
author = {L E F {Foa Torres} and H M Pastawski and S S Makler},
doi = {10.1103/PhysRevB.64.193304},
issn = {2469-9950},
year = {2001},
date = {2001-11-01},
journal = {Physical Review B},
volume = {64},
number = {19},
pages = {193304},
abstract = {Phonon-assisted tunneling in a double-barrier resonant-tunneling device
can be seen as a resonance in the electron-phonon Fock space that is
tuned by the applied voltage. We show that the geometrical parameters
can induce a symmetry condition in this space that can strongly enhance
the emission of longitudinal optical phonons, For devices with
thin-emitter barriers this is achieved by a wider collector barrier.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Phonon-assisted tunneling in a double-barrier resonant-tunneling device
can be seen as a resonance in the electron-phonon Fock space that is
tuned by the applied voltage. We show that the geometrical parameters
can induce a symmetry condition in this space that can strongly enhance
the emission of longitudinal optical phonons, For devices with
thin-emitter barriers this is achieved by a wider collector barrier.
can be seen as a resonance in the electron-phonon Fock space that is
tuned by the applied voltage. We show that the geometrical parameters
can induce a symmetry condition in this space that can strongly enhance
the emission of longitudinal optical phonons, For devices with
thin-emitter barriers this is achieved by a wider collector barrier.
Camps, I; Makler, S S; Pastawski, H M; Torres, L E F Foa
GaAs-AlxGa1-xAs double-barrier heterostructure phonon laser: A full quantum treatment Journal Article
In: Physical Review B, vol. 64, no. 12, pp. 125311, 2001, ISSN: 1098-0121.
@article{ISI:000171244400072,
title = {GaAs-AlxGa1-xAs double-barrier heterostructure phonon laser: A full quantum treatment},
author = {I Camps and S S Makler and H M Pastawski and L E F {Foa Torres}},
doi = {10.1103/PhysRevB.64.125311},
issn = {1098-0121},
year = {2001},
date = {2001-09-01},
journal = {Physical Review B},
volume = {64},
number = {12},
pages = {125311},
abstract = {The aim of this work is to describe the behavior of a device capable to
generate high-frequency (similar to THz) acoustic phonons. This device
consists in a GaAs-AlxGa1-xAs double-barrier heterostructure that, when
an external bias is applied, produces a high rate of longitudinal
optical (LO) phonons. These LO phonons are confined and they decay by
stimulated emission of a pair of secondary longitudinal optical ((LO)
over tilde) and transversal acoustic phonons. The last ones form an
intense beam of coherent acoustic phonons. To study this effect, we
start from a tight-binding Hamiltonian that takes into account the
electron-phonon and phonon-phonon interactions. We calculate the
electronic current through the double barrier and obtain a set of five
coupled kinetic equations that describes the electron and phonon
populations. The results obtained here confirm the behavior of the
terahertz phonon laser, estimated by rougher treatments [S.S. Makler
et al., J. Phys.: Condens. Matter 10, 5905 (1998)].},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The aim of this work is to describe the behavior of a device capable to
generate high-frequency (similar to THz) acoustic phonons. This device
consists in a GaAs-AlxGa1-xAs double-barrier heterostructure that, when
an external bias is applied, produces a high rate of longitudinal
optical (LO) phonons. These LO phonons are confined and they decay by
stimulated emission of a pair of secondary longitudinal optical ((LO)
over tilde) and transversal acoustic phonons. The last ones form an
intense beam of coherent acoustic phonons. To study this effect, we
start from a tight-binding Hamiltonian that takes into account the
electron-phonon and phonon-phonon interactions. We calculate the
electronic current through the double barrier and obtain a set of five
coupled kinetic equations that describes the electron and phonon
populations. The results obtained here confirm the behavior of the
terahertz phonon laser, estimated by rougher treatments [S.S. Makler
et al., J. Phys.: Condens. Matter 10, 5905 (1998)].
generate high-frequency (similar to THz) acoustic phonons. This device
consists in a GaAs-AlxGa1-xAs double-barrier heterostructure that, when
an external bias is applied, produces a high rate of longitudinal
optical (LO) phonons. These LO phonons are confined and they decay by
stimulated emission of a pair of secondary longitudinal optical ((LO)
over tilde) and transversal acoustic phonons. The last ones form an
intense beam of coherent acoustic phonons. To study this effect, we
start from a tight-binding Hamiltonian that takes into account the
electron-phonon and phonon-phonon interactions. We calculate the
electronic current through the double barrier and obtain a set of five
coupled kinetic equations that describes the electron and phonon
populations. The results obtained here confirm the behavior of the
terahertz phonon laser, estimated by rougher treatments [S.S. Makler
et al., J. Phys.: Condens. Matter 10, 5905 (1998)].
2000
Torres, L E F Foa; Pastawski, H M; Makler, S S
Resonances in Fock space: optimization of a SASER device Journal Article
In: Physica A-Statistical Mechanics and its Applications, vol. 283, no. 1-2, pp. 297-301, 2000, ISSN: 0378-4371, (VIth Latin American Workshop on Nonlinear Phenomena LAWNP'99/XIIth MEDYFINOL Conference on Statistical Physics of Dynamic and Complex Systems, CORDOBA, ARGENTINA, OCT 12-16, 1999).
@article{ISI:000088349200054,
title = {Resonances in Fock space: optimization of a SASER device},
author = {L E F {Foa Torres} and H M Pastawski and S S Makler},
doi = {10.1016/S0378-4371(00)00171-0},
issn = {0378-4371},
year = {2000},
date = {2000-08-01},
journal = {Physica A-Statistical Mechanics and its Applications},
volume = {283},
number = {1-2},
pages = {297-301},
abstract = {We model the Fock space for the electronic resonant tunneling through a
double barrier including the coherent effects of the electron-phonon
interaction. The geometry is optimized to achieve the maximal optical
phonon emission required by a SASER (ultrasound emitter) device. (C)
2000 Elsevier Science B.V. All rights reserved.},
note = {VIth Latin American Workshop on Nonlinear Phenomena LAWNP'99/XIIth
MEDYFINOL Conference on Statistical Physics of Dynamic and Complex
Systems, CORDOBA, ARGENTINA, OCT 12-16, 1999},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We model the Fock space for the electronic resonant tunneling through a
double barrier including the coherent effects of the electron-phonon
interaction. The geometry is optimized to achieve the maximal optical
phonon emission required by a SASER (ultrasound emitter) device. (C)
2000 Elsevier Science B.V. All rights reserved.
double barrier including the coherent effects of the electron-phonon
interaction. The geometry is optimized to achieve the maximal optical
phonon emission required by a SASER (ultrasound emitter) device. (C)
2000 Elsevier Science B.V. All rights reserved.