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Long Y, Ren J. Floquet topological acoustic resonators and acoustic Thouless pumping. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2019; 146:742. [PMID: 31370615 DOI: 10.1121/1.5114914] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Accepted: 02/28/2019] [Indexed: 06/10/2023]
Abstract
Constructing the topological states can serve as a promising approach for robust acoustic wave transports and manipulations. Here, the authors develop a scheme to realize acoustic topological states and adiabatic Thouless pumping in acoustic Floquet resonator systems. The directional acoustic wave can be robustly manipulated and pumped adiabatically from one side to the opposite side due to the non-trivial topological nature. The physical mechanism behind these phenomena can be understood by effective one-dimensional Aubry-André-Harper Hamiltonian, with an additional synthetic dimension originating from Floquet spatially periodic modulation. This Aubry-André-Harper acoustic resonator system can be regarded as a projection from a two-dimensional topological Hofstadter model for the integer quantum Hall effect. The authors' scheme provides a promising method for synthesizing acoustic topological states for efficient acoustic wave manipulations. Introducing the topological mechanism to the control wave will become an alternative method besides the conventional effective acoustic parameter methods.
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Affiliation(s)
- Yang Long
- Center for Phononics and Thermal Energy Science, China-EU Joint Center for Nanophononics, Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, School of Physics Sciences and Engineering, Tongji University, Shanghai 200092, People's Republic of China
| | - Jie Ren
- Center for Phononics and Thermal Energy Science, China-EU Joint Center for Nanophononics, Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, School of Physics Sciences and Engineering, Tongji University, Shanghai 200092, People's Republic of China
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2
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Quantized spin pump on helical edge states of a topological insulator. Sci Rep 2019; 9:3378. [PMID: 30833644 PMCID: PMC6399345 DOI: 10.1038/s41598-019-39002-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 12/31/2018] [Indexed: 11/08/2022] Open
Abstract
We report a theoretical study of the quantized spin pump in a traditional quantum pump device that is based on the helical edge states of a quantum spin Hall insulator. By introducing two time-dependent magnetizations out of phase as the pumping parameters, we found that when the Fermi energy resides in the energy gap opened by magnetization, an integer number of charges or spins can be pumped out in a pumping cycle and ascribed to the possible topological interface state born in between the two pumping potentials. The quantized pump current can be fully spin-polarized, spin-unpolarized, or pure spin current while its direction can be abruptly reversed by some system parameters such as the pumping phase and local gate voltage. Our findings may shed light on generation of a quantized spin pump.
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Tangpanitanon J, Bastidas VM, Al-Assam S, Roushan P, Jaksch D, Angelakis DG. Topological Pumping of Photons in Nonlinear Resonator Arrays. PHYSICAL REVIEW LETTERS 2016; 117:213603. [PMID: 27911559 DOI: 10.1103/physrevlett.117.213603] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Indexed: 06/06/2023]
Abstract
We show how to implement topological or Thouless pumping of interacting photons in one-dimensional nonlinear resonator arrays by simply modulating the frequency of the resonators periodically in space and time. The interplay between the interactions and the adiabatic modulations enables robust transport of Fock states with few photons per site. We analyze the transport mechanism via an effective analytic model and study its topological properties and its protection to noise. We conclude by a detailed study of an implementation with existing circuit-QED architectures.
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Affiliation(s)
- Jirawat Tangpanitanon
- Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543, Singapore
| | - Victor M Bastidas
- Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543, Singapore
| | - Sarah Al-Assam
- Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | | | - Dieter Jaksch
- Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543, Singapore
- Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - Dimitris G Angelakis
- Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543, Singapore
- School of Electrical and Computer Engineering, Technical University of Crete, Chania, Crete 73100, Greece
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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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5
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Eissing AK, Meden V, Kennes DM. Renormalization in Periodically Driven Quantum Dots. PHYSICAL REVIEW LETTERS 2016; 116:026801. [PMID: 26824557 DOI: 10.1103/physrevlett.116.026801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Indexed: 06/05/2023]
Abstract
We report on strong renormalization encountered in periodically driven interacting quantum dots in the nonadiabatic regime. Correlations between lead and dot electrons enhance or suppress the amplitude of driving depending on the sign of the interaction. Employing a newly developed flexible renormalization-group-based approach for periodic driving to an interacting resonant level we show analytically that the magnitude of this effect follows a power law. Our setup can act as a non-Markovian, single-parameter quantum pump.
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Affiliation(s)
- A K Eissing
- Institut für Theorie der Statistischen Physik, RWTH Aachen University and JARA-Fundamentals of Future Information Technology, 52056 Aachen, Germany
| | - V Meden
- Institut für Theorie der Statistischen Physik, RWTH Aachen University and JARA-Fundamentals of Future Information Technology, 52056 Aachen, Germany
| | - D M Kennes
- Institut für Theorie der Statistischen Physik, RWTH Aachen University and JARA-Fundamentals of Future Information Technology, 52056 Aachen, Germany
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Kaestner B, Kashcheyevs V. Non-adiabatic quantized charge pumping with tunable-barrier quantum dots: a review of current progress. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2015; 78:103901. [PMID: 26394066 DOI: 10.1088/0034-4885/78/10/103901] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Precise manipulation of individual charge carriers in nanoelectronic circuits underpins practical applications of their most basic quantum property--the universality and invariance of the elementary charge. A charge pump generates a net current from periodic external modulation of parameters controlling a nanostructure connected to source and drain leads; in the regime of quantized pumping the current varies in steps of [Formula: see text] as function of control parameters, where [Formula: see text] is the electron charge and f is the frequency of modulation. In recent years, robust and accurate quantized charge pumps have been developed based on semiconductor quantum dots with tunable tunnel barriers. These devices allow modulation of charge exchange rates between the dot and the leads over many orders of magnitude and enable trapping of a precise number of electrons far away from equilibrium with the leads. The corresponding non-adiabatic pumping protocols focus on understanding of separate parts of the pumping cycle associated with charge loading, capture and release. In this report we review realizations, models and metrology applications of quantized charge pumps based on tunable-barrier quantum dots.
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Affiliation(s)
- Bernd Kaestner
- Faculty of Physics and Mathematics, University of Latvia, LV-1002 Riga, Latvia
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7
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Napitu BD, Thijssen JM. Adiabatic and non-adiabatic charge pumping in a single-level molecular motor. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:275301. [PMID: 26086210 DOI: 10.1088/0953-8984/27/27/275301] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
We propose a design for realizing quantum charge pump based on a recent proposal for a molecular motor (Seldenthuis J S et al 2010 ACS Nano 4 6681). Our design is based on the presence of a moiety with a permanent dipole moment which can rotate, thereby modulating the couplings to metallic contacts at both ends of the molecule. Using the non-equilibrium Keldysh Green's function formalism (NEGF), we show that our design indeed generates a pump current. In the non-interacting pump, the variation of frequency from adiabatic to non-adiabatic regime, can be used to control the direction as well as the amplitude of the average current. The effect of Coulomb interaction is considered within the first- and the second- order perturbation. The numerical implementation of the scheme is quite demanding, and we develop an analytical approximation to obtain a speed-up giving results within a reasonable time. We find that the amplitude of the average pumped current can be controlled by both the driving frequency and the Coulomb interaction. The direction of of pumped current is shown to be determined by the phase difference between left and right anchoring groups.
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Affiliation(s)
- B D Napitu
- Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628CJ, Delft The Netherlands
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8
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Vovchenko V, Anchishkin D, Azema J, Lombardo P, Hayn R, Daré AM. A new approach to time-dependent transport through an interacting quantum dot within the Keldysh formalism. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2014; 26:015306. [PMID: 24292208 DOI: 10.1088/0953-8984/26/1/015306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The time-dependent transport through a nanoscale device consisting of a single spin-degenerate orbital with on-site Coulomb interaction, coupled to two leads, is investigated. Various gate and bias voltage time dependences are considered. The key and new point lies in the proposed way to avoid the difficulties of the usual heavy computation when dealing with two-time Green's functions within the Keldysh formalism. The time-dependent retarded dot Green's functions are evaluated, in an efficient manner within a non-canonical Hubbard I approximation. Calculations of the time-dependent current are then presented in the wide-band limit for different parameter sets. A comparison between the method and the Hartree-Fock approximation is performed as well. It is shown that the latter cannot account reliably for dynamical aspects of transport phenomena.
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Affiliation(s)
- V Vovchenko
- Taras Shevchenko National University of Kiev, 03022 Kiev, Ukraine
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9
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Pellegrini F, Negri C, Pistolesi F, Manini N, Santoro GE, Tosatti E. Crossover from adiabatic to antiadiabatic quantum pumping with dissipation. PHYSICAL REVIEW LETTERS 2011; 107:060401. [PMID: 21902299 DOI: 10.1103/physrevlett.107.060401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2011] [Indexed: 05/31/2023]
Abstract
Quantum pumping, in its different forms, is attracting attention from different fields, from fundamental quantum mechanics, to nanotechnology, to superconductivity. We investigate the crossover of quantum pumping from the adiabatic to the antiadiabatic regime in the presence of dissipation, and find general and explicit analytical expressions for the pumped current in a minimal model describing a system with the topology of a ring forced by a periodic modulation of frequency ω. The solution allows following in a transparent way the evolution of pumped dc current from much smaller to much larger ω values than the other relevant energy scale, the energy splitting introduced by the modulation. We find and characterize a temperature-dependent optimal value of the frequency for which the pumped current is maximal.
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10
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Oroszlány L, Zólyomi V, Lambert CJ. Carbon nanotube Archimedes screws. ACS NANO 2010; 4:7363-7366. [PMID: 21126086 DOI: 10.1021/nn1020242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Recently, nanomechanical devices composed of a long stationary inner carbon nanotube and a shorter, slowly rotating outer tube have been fabricated. In this paper, we study the possibility of using such devices as nanoscale transducers of motion into electricity. When the outer tube is chiral, we show that such devices act like quantum Archimedes screws, which utilize mechanical energy to pump electrons between reservoirs. We calculate the pumped charge from one end of the inner tube to the other, driven by the rotation of a chiral outer nanotube. We show that the pumped charge can be greater than one electron per 360° rotation, and consequently, such a device operating with a rotational frequency of 10 MHz, for example, would deliver a current of ≈1 pAmp.
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Affiliation(s)
- László Oroszlány
- Physics Department, Lancaster University, LA1 4YB Lancaster, United Kingdom.
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11
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Pan H, Yang SA, Niu Q. Pumped charge and spin current in a quantum dot molecule. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2010; 22:275302. [PMID: 21399251 DOI: 10.1088/0953-8984/22/27/275302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The effects of an ac electric field on the quantum transport behaviors in a parallel-coupled double quantum dot system are investigated theoretically. A dc charge current can be pumped at zero bias due to photon-assisted tunneling effects. The sign, magnitude and position of the pumped current peaks can be well controlled and manipulated by simply varying the gate voltage, the amplitude and frequency of the ac field. Furthermore, the possibility of electrically pumping a pure spin current in the presence of spin-orbit interaction is discussed.
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Affiliation(s)
- Hui Pan
- Department of Physics, The University of Texas at Austin, Austin, TX 78712, USA
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12
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Andergassen S, Meden V, Schoeller H, Splettstoesser J, Wegewijs MR. Charge transport through single molecules, quantum dots and quantum wires. NANOTECHNOLOGY 2010; 21:272001. [PMID: 20571187 DOI: 10.1088/0957-4484/21/27/272001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
We review recent progress in the theoretical description of correlation and quantum fluctuation phenomena in charge transport through single molecules, quantum dots and quantum wires. Various physical phenomena are addressed, relating to cotunneling, pair-tunneling, adiabatic quantum pumping, charge and spin fluctuations, and inhomogeneous Luttinger liquids. We review theoretical many-body methods to treat correlation effects, quantum fluctuations, non-equilibrium physics, and the time evolution into the stationary state of complex nanoelectronic systems.
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Affiliation(s)
- S Andergassen
- Institut für Theoretische Physik A, RWTH Aachen, 52056 Aachen, Germany
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13
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Reckermann F, Splettstoesser J, Wegewijs MR. Interaction-induced adiabatic nonlinear transport. PHYSICAL REVIEW LETTERS 2010; 104:226803. [PMID: 20867193 DOI: 10.1103/physrevlett.104.226803] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2010] [Indexed: 05/29/2023]
Abstract
We calculate the time-dependent nonlinear transport current through an interacting quantum dot in the single-electron tunneling (SET) regime. We show that an additional dc current is generated by the electron-electron interaction by adiabatic out-of-phase modulation of the gate and bias voltage. This current can arise only when two SET resonance conditions are simultaneously satisfied. We propose an adiabatic transport spectroscopy where lock-in measurement of a "time-averaged stability diagram" probes interactions, tunnel asymmetries, and changes in the ground state spin degeneracy.
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Affiliation(s)
- Felix Reckermann
- Institut für Festkörper-Forschung-Theorie 3, Forschungszentrum Jülich, 52425 Jülich, Germany
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14
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Cavaliere F, Governale M, König J. Nonadiabatic pumping through interacting quantum dots. PHYSICAL REVIEW LETTERS 2009; 103:136801. [PMID: 19905533 DOI: 10.1103/physrevlett.103.136801] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2009] [Indexed: 05/28/2023]
Abstract
We study nonadiabatic two-parameter charge and spin pumping through a single-level quantum dot with Coulomb interaction. For the limit of weak tunnel coupling and in the regime of pumping frequencies up to the tunneling rates, Omega less, similar Gamma/variant Planck's over 2pi, we perform an exact resummation of contributions of all orders in the pumping frequency. As striking nonadiabatic signatures, we find frequency-dependent phase shifts in the charge and spin currents, which opens the possibility to control charge and spin currents by tuning the pumping frequency. This includes the realization of an effective single-parameter pumping as well as pure spin without charge currents.
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Affiliation(s)
- Fabio Cavaliere
- CNR-INFM LAMIA, Dipartimento di Fisica, Università di Genova, 16146 Genova, Italy
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15
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Ol'khovskaya S, Splettstoesser J, Moskalets M, Büttiker M. Shot noise of a mesoscopic two-particle collider. PHYSICAL REVIEW LETTERS 2008; 101:166802. [PMID: 18999699 DOI: 10.1103/physrevlett.101.166802] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2008] [Indexed: 05/27/2023]
Abstract
We investigate the shot noise generated by particle emission from a mesoscopic capacitor into an edge state coupled to another edge state at a quantum point contact (QPC). For a capacitor subject to a periodic voltage the resulting shot noise is proportional to the number of particles (both electrons and holes) emitted during a period. The shot noise is proportional to the driving frequency, however it is independent of the applied voltage. If two capacitors are coupled to a QPC at different sides then the resulting shot noise is maximally the sum of noises produced by each of the capacitors. However, the noise is suppressed if particles of the same kind are emitted simultaneously.
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Affiliation(s)
- S Ol'khovskaya
- Department of Metal and Semiconductor Physics, NTU Kharkiv Polytechnic Institute, Kharkiv, Ukraine
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16
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Buitelaar MR, Kashcheyevs V, Leek PJ, Talyanskii VI, Smith CG, Anderson D, Jones GAC, Wei J, Cobden DH. Adiabatic charge pumping in carbon nanotube quantum dots. PHYSICAL REVIEW LETTERS 2008; 101:126803. [PMID: 18851400 DOI: 10.1103/physrevlett.101.126803] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2008] [Indexed: 05/26/2023]
Abstract
We investigate charge pumping in carbon nanotube quantum dots driven by the electric field of a surface acoustic wave. We find that, at small driving amplitudes, the pumped current reverses polarity as the conductance is tuned through a Coulomb blockade peak using a gate electrode. We study the behavior as a function of wave amplitude, frequency, and direction and develop a model in which our results can be understood as resulting from adiabatic charge redistribution between the leads and quantum dots on the nanotube.
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Affiliation(s)
- M R Buitelaar
- Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom
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17
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Braun M, Burkard G. Nonadiabatic two-parameter charge and spin pumping in a quantum dot. PHYSICAL REVIEW LETTERS 2008; 101:036802. [PMID: 18764273 DOI: 10.1103/physrevlett.101.036802] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2008] [Indexed: 05/26/2023]
Abstract
We study dc charge and spin transport through a weakly coupled quantum dot, driven by a nonadiabatic periodic change of system parameters. We generalize the model of Tien and Gordon to simultaneously oscillating voltages and tunnel couplings. When applying our general result to the two-parameter charge pumping in quantum dots, we find interference effects between the oscillations of the voltage and tunnel couplings. We show that these interference effects may explain recent measurements in metallic islands. Furthermore, we discuss the possibility to electrically pump a spin current in presence of a static magnetic field.
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Affiliation(s)
- Matthias Braun
- Institute of Theoretical Physics C, RWTH Aachen University, D-52056 Aachen, Germany
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18
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Fioretto D, Silva A. Phase coherence, inelastic scattering, and interaction corrections in pumping through quantum dots. PHYSICAL REVIEW LETTERS 2008; 100:236803. [PMID: 18643534 DOI: 10.1103/physrevlett.100.236803] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2007] [Indexed: 05/26/2023]
Abstract
Adiabatic quantum pumping in noninteracting, phase coherent quantum dots is elegantly described by Brouwer's formula. Interactions within the dot, while suppressing phase coherence, make Brouwer's formalism inapplicable. In this Letter, we discuss the nature of the physical processes forcing a description of pumping beyond Brouwer's formula, and develop, using a controlled adiabatic expansion, a useful formalism to study the effect of interactions within a generic perturbative scheme. The pumped current consists of a first contribution, analogous to Brouwer's formula and accounting for the remanent coherence, and of interaction corrections describing inelastic scattering. We apply the formalism to study the effect of interaction with a bosonic bath on a resonant level pump and discuss the robustness of the quantization of the pumped charge in turnstile cycles.
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Affiliation(s)
- Davide Fioretto
- Dipartimento di Fisica, Universita' degli Studi di Milano, Milano, Italy
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19
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Sela E, Oreg Y. Adiabatic pumping in interacting systems. PHYSICAL REVIEW LETTERS 2006; 96:166802. [PMID: 16712255 DOI: 10.1103/physrevlett.96.166802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2005] [Indexed: 05/09/2023]
Abstract
A dc current can be pumped through an interacting system by periodically varying two independent parameters such as the magnetic field and a gate potential. We present a general expression for the adiabatic pumping current in interacting systems, written in terms of instantaneous properties of the system at equilibrium, and find the limits of its applicability. This expression generalizes the scattering approach for noninteracting particles. We apply our formula for a quantum critical system that exhibits the two-channel Kondo effect, where single particle excitations are not well defined. We find that if the quantum critical point is contained in the pumping trajectory, the pumped spin between the channels approaches h, and if it is not contained in the trajectory, the spin approaches zero when the temperature T --> 0. We discuss the non-Fermi liquid features of this system at finite T.
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Affiliation(s)
- Eran Sela
- Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot, 76100, Israel
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