Time-dependent transport in interacting and noninteracting resonant-tunneling systems

Jauho, Antti–Pekka; Wingreen, Ned S.; Meir, Yigal

doi:10.1103/physrevb.50.5528

Cited by 1,894 publications

(1,897 citation statements)

References 40 publications

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“…Electric current flowing from the β-th lead to the quantum dot in a nonequilibrium situation is determined by the retarded (advanced) G r(a) σ and correlation (lesser) G < σ Green functions of the dot (calculated in the presence of coupling to the electrodes), and is given by the formula [30] …”

Section: Theoretical Formulationmentioning

confidence: 99%

Spin-polarized transport through a single-level quantum dot in the Kondo regime

Świrkowicz¹,

Wilczyński²,

Barnaś³

2006

J. Phys.: Condens. Matter

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Nonequilibrium electronic transport through a quantum dot coupled to ferromagnetic leads (electrodes) is studied theoretically by the nonequilibrium Green function technique. The system is described by the Anderson model with arbitrary correlation parameter U . Exchange interaction between the dot and ferromagnetic electrodes is taken into account via an effective molecular field. The following situations are analyzed numerically: (i) the dot is symmetrically coupled to two ferromagnetic leads, (ii) one of the two ferromagnetic leads is half-metallic with almost total spin polarization of electron states at the Fermi level, and (iii) one of the two electrodes is nonmagnetic whereas the other one is ferromagnetic. Generally, the Kondo peak in the density of states (DOS) becomes spin-split when the total exchange field acting on the dot is nonzero. The spin-splitting of the Kondo peak in DOS leads to splitting and suppression of the corresponding zero bias anomaly in the differential conductance.

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Section: Theoretical Formulationmentioning

confidence: 99%

Spin-polarized transport through a single-level quantum dot in the Kondo regime

Świrkowicz¹,

Wilczyński²,

Barnaś³

2006

J. Phys.: Condens. Matter

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“…We use the NEGF approach [14,15] to describe transport in this open quantum system. Given the retarded Green function of the isolated molecular system…”

mentioning

confidence: 99%

Controlling Quantum Transport through a Single Molecule

2006

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We investigate multi-terminal quantum transport through single monocyclic aromatic annulene molecules, and their derivatives, using the nonequilibrium Green function approach in the selfconsistent Hartree-Fock approximation. A new device concept, the Quantum Interference Effect Transistor (QuIET) is proposed, exploiting perfect destructive interference stemming from molecular symmetry, and controlling current flow by introducing decoherence and/or elastic scattering that break the symmetry. This approach overcomes the fundamental problems of power dissipation and environmental sensitivity that beset many nanoscale device proposals.PACS numbers: 85.65.+h, 31.15.Ne, 03.65.Yz From the vacuum tube to the modern CMOS transistor, devices which control the flow of electrical current by modulating an electron energy barrier are ubiquitous in electronics. In this paradigm, a minimum energy of k B T must be dissipated to switch the current "on" and "off," necessitating incredible power dissipation at device densities approaching the atomic limit [1]. A possible alternative is to control electron flow using quantum interference [2,3,4,5]. In mesoscopic devices, quantum interference is typically tuned via the Aharanov-Bohm effect [6]; however, in nanoscale conductors such as single molecules, this is impractical due to the enormous magnetic fields required to produce a phase shift of order one radian. Similarly, a device based on an electrostatic phase shift [3,4] would, in small molecules, require voltages incompatible with structural stability. We propose a solution exploiting perfect destructive interference stemming from molecular symmetry, and controlling quantum transport by introducing decoherence or scattering from a third lead.As daunting as the fundamental problem of the switching mechanism, is the practical problem of nanofabrication [1]. In this respect, single molecules have a distinct advantage over other types of nanostructures, in that large numbers of identical devices can be readily synthesized. Single-molecule devices with two leads have been fabricated by a number of techniques [7]. Our transistor requires a third terminal coupled locally to the molecule, capacitively or via tunneling (see Fig. 1). To date, only global gating of single-molecule devices has been achieved [7]; recently, however, there has been significant progress toward a locally coupled third terminal [8].This Letter reports the results of our recent theoretical investigations into the use of interference effects to create molecular transistors, leading to a new device concept, which we call the Quantum Interference Effect Transistor (QuIET). We demonstrate that for all monocyclic aromatic annulenes, particular two-terminal configurations exist in which destructive interference blocks current flow, and that transistor behavior can be achieved by supplying tunable decoherence or scattering at a third site. We also propose a realistic model for introducing scattering in a controllable way, using an alkene chain of arbitrary length (cf. ...

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“…Having found the Green functions, one can calculate the current flowing through the junction using the general formula [19,20],…”

Section: Model and Methodsmentioning

confidence: 99%

Phonon-assisted Andreev reflection in a hybrid junction based on a quantum dot

Bocian

Rudziński

2015

Eur. Phys. J. B

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Abstract. Spin-dependent tunneling through a quantum dot coupled to one ferromagnetic and one superconducting electrodes is investigated in the Andreev reflection (AR) regime occurring in the presence of the on-dot electron-phonon interactions. Current-voltage characteristics of the system are evaluated within the nonequilibrium Green function technique. Features of the AR current due to interplay between the electron-phonon interactions, intradot Coulomb correlations and the polarization of the ferromagnetic electrode are analyzed in both linear and nonlinear transport regimes. It is shown that for the case of electron-hole symmetry, the phonon resonances may appear on both sides of the main elastic resonances in spectral function. A phonon-induced renormalization of the Andreev transmission levels is found and splitting of the phonon side bands for nonvanishing intradot Coulomb repulsion is observed. It is shown that linear conductance exhibits the polaron shift and suppression in the presence of the polaron transmission. In nonequilibrium situation the mechanism of the negative differential conductance (NDC) in the presence of competing magnetic electrode polarisation and the Coulomb correlations on the dot is analyzed. An influence of the polaron transmission through the Andreev intradot states on the NDC oscillations is also discussed.

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Time-dependent transport in interacting and noninteracting resonant-tunneling systems

Cited by 1,894 publications

References 40 publications

Spin-polarized transport through a single-level quantum dot in the Kondo regime

Spin-polarized transport through a single-level quantum dot in the Kondo regime

Controlling Quantum Transport through a Single Molecule

Phonon-assisted Andreev reflection in a hybrid junction based on a quantum dot

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