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Zeng Y, Crépel V, Millis AJ. Keldysh Field Theory of Dynamical Exciton Condensation Transitions in Nonequilibrium Electron-Hole Bilayers. PHYSICAL REVIEW LETTERS 2024; 132:266001. [PMID: 38996303 DOI: 10.1103/physrevlett.132.266001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 05/16/2024] [Accepted: 05/31/2024] [Indexed: 07/14/2024]
Abstract
Recent experiments have realized steady-state electrical injection of interlayer excitons in electron-hole bilayers subject to a large bias voltage. In the ideal case in which interlayer tunneling is negligibly weak, the system is in quasiequilibrium with a reduced effective band gap. Interlayer tunneling introduces a current and drives the system out of equilibrium. In this work we derive a nonequilibrium field theory description of interlayer excitons in biased electron-hole bilayers. In the large bias limit, we find that p-wave interlayer tunneling reduces the effective band gap and increases the effective temperature for intervalley excitons. We discuss possible experimental implications for InAs/GaSb quantum wells and transition metal dichalcogenide bilayers.
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Affiliation(s)
- Yongxin Zeng
- Department of Physics, Columbia University, New York, New York 10027, USA
- Center for Computational Quantum Physics, Flatiron Institute, New York, New York 10010, USA
- Department of Physics, University of Texas at Austin, Austin, Texas 78712, USA
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Thoss M, Evers F. Perspective: Theory of quantum transport in molecular junctions. J Chem Phys 2018; 148:030901. [DOI: 10.1063/1.5003306] [Citation(s) in RCA: 105] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Michael Thoss
- Institute of Physics, University of Freiburg, Hermann-Herder-Str. 3, D-79104 Freiburg, Germany
| | - Ferdinand Evers
- Institute of Theoretical Physics, University of Regensburg, Universitätsstr. 31, D-93053 Regensburg, Germany
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Ourabah K, Tribeche M. Quantum entanglement and temperature fluctuations. Phys Rev E 2017; 95:042111. [PMID: 28505779 DOI: 10.1103/physreve.95.042111] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Indexed: 11/07/2022]
Abstract
In this paper, we consider entanglement in a system out of equilibrium, adopting the viewpoint given by the formalism of superstatistics. Such an approach yields a good effective description for a system in a slowly fluctuating environment within a weak interaction between the system and the environment. For this purpose, we introduce an alternative version of the formalism within a quantum mechanical picture and use it to study entanglement in the Heisenberg XY model, subject to temperature fluctuations. We consider both isotropic and anisotropic cases and explore the effect of different temperature fluctuations (χ^{2}, log-normal, and F distributions). Our results suggest that particular fluctuations may enhance entanglement and prevent it from vanishing at higher temperatures than those predicted for the same system at thermal equilibrium.
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Affiliation(s)
- Kamel Ourabah
- Theoretical Physics Laboratory, Faculty of Physics, University of Bab-Ezzouar, USTHB, Boîte Postale 32, El Alia, Algiers 16111, Algeria
| | - Mouloud Tribeche
- Theoretical Physics Laboratory, Faculty of Physics, University of Bab-Ezzouar, USTHB, Boîte Postale 32, El Alia, Algiers 16111, Algeria.,Algerian Academy of Sciences and Technologies, Algiers, Algeria
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Nocera A, Perroni CA, Ramaglia VM, Cataudella V. Charge and heat transport in soft nanosystems in the presence of time-dependent perturbations. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2016; 7:439-64. [PMID: 27335736 PMCID: PMC4901550 DOI: 10.3762/bjnano.7.39] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 02/08/2016] [Indexed: 06/06/2023]
Abstract
BACKGROUND Soft nanosystems are electronic nanodevices, such as suspended carbon nanotubes or molecular junctions, whose transport properties are modulated by soft internal degrees of freedom, for example slow vibrational modes. Effects of the electron-vibration coupling on the charge and heat transport of soft nanoscopic systems are theoretically investigated in the presence of time-dependent perturbations, such as a forcing antenna or pumping terms between the leads and the nanosystem. A well-established approach valid for non-equilibrium adiabatic regimes is generalized to the case where external time-dependent perturbations are present. Then, a number of relevant applications of the method are reviewed for systems composed by a quantum dot (or molecule) described by a single electronic level coupled to a vibrational mode. RESULTS Before introducing time-dependent perturbations, the range of validity of the adiabatic approach is discussed showing that a very good agreement with the results of an exact quantum calculation is obtained in the limit of low level occupation. Then, we show that the interplay between the low frequency vibrational modes and the electronic degrees of freedom affects the thermoelectric properties within the linear response regime finding out that the phonon thermal conductance provides an important contribution to the figure of merit at room temperature. Our work has been stimulated by recent experimental results on carbon nanotube electromechanical devices working in the semiclassical regime (resonator frequencies in the megahertz range compared to an electronic hopping frequency of the order of tens of gigahertz) with extremely high quality factors. The nonlinear vibrational regime induced by the external antenna in such systems has been discussed within the non-perturbative adiabatic approach reproducing quantitatively the characteristic asymmetric shape of the current-frequency curves. Within the same set-up, we have proved that the antenna is able to pump sufficient charge close to the mechanical resonance making single-parameter adiabatic charge pumping feasible in carbon nanotube resonators. The pumping mechanism that we observe is different from that acting in the two parameter pumping and, instead, it is based on an important dynamic adjustment of the mechanical motion of the nanotube to the external drive in the weakly nonlinear regime. Finally, stochastic forces induced by quantum and thermal fluctuations due to the electron charging of the quantum dot are shown to affect in a significant way a Thouless charge pump realized with an elastically deformable quantum dot. In this case, the pumping mechanism is also shown to be magnified when the frequency of the external drive is resonant with the proper frequency of the deformable quantum dot. In this regime, the pumping current is not strongly reduced by the temperature, giving a measurable effect. CONCLUSION Aim of this review has been to discuss common features of different soft nanosystems under external drive. The most interesting effects induced by time-dependent perturbations are obtained when the external forcing is nearly resonant with the slow vibrational modes. Indeed, not only the external forcing can enhance the electronic response, but it also induces nonlinear regimes where the interplay between electronic and vibrational degrees of freedom plays a major role.
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Affiliation(s)
- Alberto Nocera
- Department of Physics, Northeastern University, Boston, MA 02115, USA
| | - Carmine Antonio Perroni
- CNR-SPIN and Department of Physics “Ettore Pancini”, Universita’ degli Studi di Napoli Federico II, Complesso Universitario Monte Sant’Angelo, Via Cintia, I-80126 Napoli, Italy
| | - Vincenzo Marigliano Ramaglia
- CNR-SPIN and Department of Physics “Ettore Pancini”, Universita’ degli Studi di Napoli Federico II, Complesso Universitario Monte Sant’Angelo, Via Cintia, I-80126 Napoli, Italy
| | - Vittorio Cataudella
- CNR-SPIN and Department of Physics “Ettore Pancini”, Universita’ degli Studi di Napoli Federico II, Complesso Universitario Monte Sant’Angelo, Via Cintia, I-80126 Napoli, Italy
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Säkkinen N, Peng Y, Appel H, van Leeuwen R. Many-body Green’s function theory for electron-phonon interactions: The Kadanoff-Baym approach to spectral properties of the Holstein dimer. J Chem Phys 2015; 143:234102. [DOI: 10.1063/1.4936143] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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Ding GH, Dong B. Phonon effects on the current noise spectra and the ac conductance of a single molecular junction. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2014; 26:305301. [PMID: 25008584 DOI: 10.1088/0953-8984/26/30/305301] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
By using nonequilibrium Green's functions and the equation of motion method, we formulate a self-consistent field theory for the electron transport through a single-molecule junction (SMJ) coupled with a vibrational mode. We show that the nonequilibrium dynamics of the phonons in a strong electron-phonon coupling regime can be taken into account appropriately in this self-consistent perturbation theory, and the self-energy of the phonons is connected with the current fluctuations in the molecular junction. We calculate the finite-frequency nonsymmetrized noise spectra and the ac conductance, which reveal a wealth of inelastic electron tunneling characteristics on the absorption and emission properties of this SMJ. In the presence of a finite bias voltage and the electron tunneling current, the vibration mode of the molecular junction is heated and driven to an unequilibrated state. The influences of unequilibrated phonons on the current and the noise spectra are investigated.
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Affiliation(s)
- Guo-Hui Ding
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China
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Green Function Techniques in the Treatment of Quantum Transport at the Molecular Scale. SPRINGER SERIES IN CHEMICAL PHYSICS 2009. [DOI: 10.1007/978-3-642-02306-4_9] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Galperin M, Ratner MA, Nitzan A, Troisi A. Nuclear Coupling and Polarization in Molecular Transport Junctions: Beyond Tunneling to Function. Science 2008; 319:1056-60. [DOI: 10.1126/science.1146556] [Citation(s) in RCA: 255] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Han JE, Heary RJ. Imaginary-time formulation of steady-state nonequilibrium: application to strongly correlated transport. PHYSICAL REVIEW LETTERS 2007; 99:236808. [PMID: 18233398 DOI: 10.1103/physrevlett.99.236808] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2007] [Indexed: 05/25/2023]
Abstract
We extend the imaginary-time formulation of the equilibrium quantum many-body theory to steady-state nonequilibrium with an application to strongly correlated transport. By introducing the Matsubara voltage, we maintain the finite chemical potential shifts in the Fermi-Dirac function, in agreement with the Keldysh formulation. The formulation is applied to strongly correlated transport in the Kondo regime using the quantum Monte Carlo method.
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Affiliation(s)
- J E Han
- Department of Physics, State University of New York at Buffalo, Buffalo, New York 14260, USA
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Yeganeh S, Galperin M, Ratner MA. Switching in Molecular Transport Junctions: Polarization Response. J Am Chem Soc 2007; 129:13313-20. [DOI: 10.1021/ja0730967] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Sina Yeganeh
- Contribution from the Department of Chemistry, Center for Nanofabrication and Molecular Self Assembly, and Materials Research Science and Engineering Center, Northwestern University, Evanston, Illinois 60208-3113
| | - Michael Galperin
- Contribution from the Department of Chemistry, Center for Nanofabrication and Molecular Self Assembly, and Materials Research Science and Engineering Center, Northwestern University, Evanston, Illinois 60208-3113
| | - Mark A. Ratner
- Contribution from the Department of Chemistry, Center for Nanofabrication and Molecular Self Assembly, and Materials Research Science and Engineering Center, Northwestern University, Evanston, Illinois 60208-3113
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Mitra A, Takei S, Kim YB, Millis AJ. Nonequilibrium quantum criticality in open electronic systems. PHYSICAL REVIEW LETTERS 2006; 97:236808. [PMID: 17280229 DOI: 10.1103/physrevlett.97.236808] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2006] [Indexed: 05/13/2023]
Abstract
A theory is presented of quantum criticality in open (coupled to reservoirs) itinerant-electron magnets, with nonequilibrium drive provided by current flow across the system. Both departures from equilibrium at conventional (equilibrium) quantum critical points and the physics of phase transitions induced by the nonequilibrium drive are treated. Nonequilibrium-induced phase transitions are found to have the same leading critical behavior as conventional thermal phase transitions.
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Affiliation(s)
- Aditi Mitra
- Department of Physics, University of Toronto, 60 St. George Street, Toronto, Ontario M5S 1A7, Canada
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Keane ZK, Ciszek JW, Tour JM, Natelson D. Three-terminal devices to examine single-molecule conductance switching. NANO LETTERS 2006; 6:1518-21. [PMID: 16834442 DOI: 10.1021/nl061117+] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
We report electronic transport measurements of single-molecule transistor devices incorporating bipyridyl-dinitro oligophenylene-ethynylene dithiol (BPDN-DT), a molecule known to exhibit conductance switching in other measurement configurations. We observe hysteretic conductance switching in 8% of devices with measurable currents and find that dependence of the switching properties on gate voltage is rare when compared to other single-molecule transistor devices. This suggests that polaron formation is unlikely to be responsible for switching in these devices. We discuss this and alternative switching mechanisms.
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Affiliation(s)
- Z K Keane
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
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Koch J, von Oppen F. Franck-Condon blockade and giant Fano factors in transport through single molecules. PHYSICAL REVIEW LETTERS 2005; 94:206804. [PMID: 16090269 DOI: 10.1103/physrevlett.94.206804] [Citation(s) in RCA: 130] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2004] [Indexed: 05/03/2023]
Abstract
We show that Franck-Condon physics leads to a significant current suppression at low bias voltages (termed Franck-Condon blockade) in transport through single molecules with strong coupling between electronic and vibrational degrees of freedom. Transport in this regime is characterized by remarkably large Fano factors (10(2)-10(3) for realistic parameters), which arise due to avalanchelike transport of electrons. Avalanches occur in a self-similar manner over a wide range of time scales, leading to power-law dependences of the current noise on frequency and vibrational relaxation rate.
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Affiliation(s)
- Jens Koch
- Institut für Theoretische Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
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