2008 | |
Coiffic, J C; Foa Torres, L E; Poche, Le H; Fayolle, M; Roche, S; Maitrejean, S; Roualdes, S; Ayral, A An application of carbon nanotubes for integrated circuit interconnects Journal Article Carbon Nanotubes and Associated Devices, 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; Foa Torres, L E F; Poche, Le H Conduction regime in innovative carbon nanotube via interconnect architectures Journal Article Applied Physics Letters, 91 (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. | |
Roche, Stephan; Jiang, Jie; Foa Torres, Luis E F; Saito, Riichiro Charge transport in carbon nanotubes: quantum effects of electron-phonon coupling Journal Article Journal of Physics-Condensed Matter, 19 (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. | |
Foa Torres, Luis E F; Roche, Stephan Diameter dependent phonon-induced backscattering in semiconducting carbon nanotubes Journal Article Physical Review B, 75 (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. | |
Foa Torres, L E F; Roche, S Electron-phonon induced conductance gaps in carbon nanotubes Journal Article Applied Physics A-Materials Science & Processing, 86 (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. | |
Pastawski, H M; Danieli, E P; Calvo, H L; Foa Torres, L E F Towards a time reversal mirror for quantum systems Journal Article EPL, 77 (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. | |
Foa Torres, L E F; Roche, S Effects of electron-phonon interaction on transport through carbon nanotubes: lifting of degeneracies in Fock-space Journal Article Journal of Physics: Conference Series, 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 | |
Foa Torres, Luis E F; Roche, Stephan Inelastic quantum transport and peierls-like mechanism in carbon nanotubes Journal Article Physical Review Letters, 97 (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). | |
Foa Torres, L E F; Pastawski, H M; Medina, E Antiresonances as precursors of decoherence Journal Article Europhysics Letters, 73 (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. | |
2005 | |
Foa Torres, L E F Mono-parametric quantum charge pumping: Interplay between spatial interference and photon-assisted tunneling Journal Article Physical Review B, 72 (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. | |
2004 | |
Foa Torres, L E F; Lewenkopf, C H; Pastawski, H M Conductance fluctuations in Coulomb-blockaded dots: from the sequential theory to a quantum coherent description Journal Article PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES, 22 (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. | |
2003 | |
Foa Torres, L E F; Lewenkopf, C H; Pastawski, H M Coherent versus sequential electron tunneling in quantum dots Journal Article Physical Review Letters, 91 (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. | |
2002 | |
Pastawski, H M; Foa Torres, L E F; Medina, E Electron-phonon interaction and electronic decoherence in molecular conductors Journal Article Chemical Physics, 281 (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. | |
Foa Torres, L E F; Pastawski, H M; Makler, S S Electron-phonon interaction in electronic tunneling: From sequential rate equations to a coherent description Journal Article Brazilian Journal of Physics, 32 (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. | |
Foa Torres, L E F; Pastawski, H M; Makler, S S An ultrasound emitter based on assisted tunneling Journal Article Solid State Communications, 124 (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. | |
2001 | |
Foa Torres, L E F; Pastawski, H M; Makler, S S Tuning a resonance in Fock space: Optimization of phonon emission in a resonant-tunneling device Journal Article Physical Review B, 64 (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. | |
Camps, I; Makler, S S; Pastawski, H M; Foa Torres, L E F GaAs-AlxGa1-xAs double-barrier heterostructure phonon laser: A full quantum treatment Journal Article Physical Review B, 64 (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)]. | |
2000 | |
Foa Torres, L E F; Pastawski, H M; Makler, S S Resonances in Fock space: optimization of a SASER device Journal Article Physica A-Statistical Mechanics and its Applications, 283 (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. | |
2008 | |
An application of carbon nanotubes for integrated circuit interconnects Journal Article Carbon Nanotubes and Associated Devices, 7037 , pp. 70370D, 2008. | |
2007 | |
Conduction regime in innovative carbon nanotube via interconnect architectures Journal Article Applied Physics Letters, 91 (25), 2007, ISSN: 0003-6951. | |
Charge transport in carbon nanotubes: quantum effects of electron-phonon coupling Journal Article Journal of Physics-Condensed Matter, 19 (18), pp. 183203, 2007, ISSN: 0953-8984, (Invited Topical Review). | |
Diameter dependent phonon-induced backscattering in semiconducting carbon nanotubes Journal Article Physical Review B, 75 (15), pp. 153402, 2007, ISSN: 2469-9950. | |
Electron-phonon induced conductance gaps in carbon nanotubes Journal Article Applied Physics A-Materials Science & Processing, 86 (3), pp. 283-288, 2007, ISSN: 0947-8396. | |
Towards a time reversal mirror for quantum systems Journal Article EPL, 77 (4), pp. 40001, 2007, ISSN: 0295-5075. | |
Effects of electron-phonon interaction on transport through carbon nanotubes: lifting of degeneracies in Fock-space Journal Article Journal of Physics: Conference Series, 92 , pp. 012057, 2007, ISSN: 1742-6596. | |
2006 | |
Inelastic quantum transport and peierls-like mechanism in carbon nanotubes Journal Article Physical Review Letters, 97 (7), pp. 076804, 2006, ISSN: 0031-9007. | |
Antiresonances as precursors of decoherence Journal Article Europhysics Letters, 73 (2), pp. 164-170, 2006, ISSN: 0295-5075. | |
2005 | |
Mono-parametric quantum charge pumping: Interplay between spatial interference and photon-assisted tunneling Journal Article Physical Review B, 72 (24), pp. 245339, 2005, ISSN: 2469-9950. | |
2004 | |
Conductance fluctuations in Coulomb-blockaded dots: from the sequential theory to a quantum coherent description Journal Article PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES, 22 (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). | |
2003 | |
Coherent versus sequential electron tunneling in quantum dots Journal Article Physical Review Letters, 91 (11), pp. 116801, 2003, ISSN: 0031-9007. | |
2002 | |
Electron-phonon interaction and electronic decoherence in molecular conductors Journal Article Chemical Physics, 281 (2-3, SI), pp. 257-278, 2002, ISSN: 0301-0104. | |
Electron-phonon interaction in electronic tunneling: From sequential rate equations to a coherent description Journal Article Brazilian Journal of Physics, 32 (2), pp. 300-302, 2002, ISSN: 0103-9733, (10th Brazillian Workshop on Semiconductor Physics (BWSP 10), GUARUJA, BRAZIL, APR 22-27, 2001). | |
An ultrasound emitter based on assisted tunneling Journal Article Solid State Communications, 124 (10-11), pp. 363-371, 2002, ISSN: 0038-1098. | |
2001 | |
Tuning a resonance in Fock space: Optimization of phonon emission in a resonant-tunneling device Journal Article Physical Review B, 64 (19), pp. 193304, 2001, ISSN: 2469-9950. | |
GaAs-AlxGa1-xAs double-barrier heterostructure phonon laser: A full quantum treatment Journal Article Physical Review B, 64 (12), pp. 125311, 2001, ISSN: 1098-0121. | |
2000 | |
Resonances in Fock space: optimization of a SASER device Journal Article Physica A-Statistical Mechanics and its Applications, 283 (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). | |