Transient behavior of heat transport in a thermal switch

Cuansing, Eduardo C.; Wang, Jian‐Sheng

doi:10.1103/physrevb.81.052302

Cited by 37 publications

(11 citation statements)

References 18 publications

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“…where j = 1, 2. Inspecting (30) we conclude that the currents flowing between the QD and a given superconducting lead does not depend on spin, j S1σ (t) = j S1−σ (t), irrespective of the spin dependent QD energy levels. This is a consequence of the fact that the QD can exchange charge with the superconducting leads only vi pairs of opposite spin electrons.…”

Section: Subgap Currentsmentioning

confidence: 89%

“…25 The transient dynamics has been also studied for QD after a sudden symmetrical connection to the leads 27,37,78,85 or asymmetrically coupled to electrodes following a sudden change of the QD energy levels. 11 The transient heat generation driven by a step-like pulse bias with the Anderson-Holstein model or the timedependent current through QD suddenly coupled to a vibrational mode have been studied in nanostructures with the normal 19,30,47,56,63 or superconducting electrodes. 71 Technological progress in the real-time detection of single electrons has opened a possibility for studying electron transport from a perspective of the stochastic processes.…”

Section: Introductionmentioning

confidence: 99%

“…Such hybrid nanostructures with QD between the normal and superconducting electrodes, reveal many interesting effects with potential applications in nanoelectronics, spintronics or quantum computing. 29,30,42,63,64 The superconducting reservoir af-fects the QD via proximity effect, and could be responsible for the Cooper-pair tunneling and Josephson currents, even in absence of any bias voltages. Additional normal electrode coupled to the system allows for good control of the electron transport [86][87][88][89] and could significantly affect the transient phenomena.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Time-dependent Andreev bound states of a quantum dot coupled to two superconducting leads

Taranko,

Kwapinski,

Domanski

2018

Preprint

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Sub-gap transport properties of a quantum dot (QD) coupled to two superconducting and one metallic leads are studied theoretically, solving the time-dependent equation of motion by the Laplace transform technique. We focus on time-dependent response of the system induced by a sudden switching on the QD-leads couplings, studying the influence of initial conditions on the transient currents and the differential conductance. We derive analytical expressions for measurable quantities and find that they oscillate in time with the frequency governed by the QD-superconducting lead coupling and acquire damping, due to relaxation driven by the normal lead. Period of these oscillations increases with the superconducting phase difference φ. In particular, for φ = π the QD occupancy and the normal current evolve monotonically (without any oscillations) to their stationary values. In such case the induced electron pairing vanishes and the superconducting current is completely blocked. We also analyze time-dependent development of the Andreev bound states. We show, that the measurable conductance peaks do not appear immediately after sudden switching of the QD coupling to external leads but it takes some finite time-interval for the system needs create these Andreev states. Such time-delay is mainly controlled by the QD-normal lead coupling.

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Section: Subgap Currentsmentioning

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Time-dependent Andreev bound states of a quantum dot coupled to two superconducting leads

Taranko,

Kwapinski,

Domanski

2018

Preprint

View full text Add to dashboard Cite

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“…However, the time-dependent phonon current in the transient regime is also an important question. Recently, the transient phonon transport was studied in arbitrary harmonic systems connected to phonon baths by abruptly turning on the coupling between leads within the partition scheme based on the NEGF method 83,84 .…”

Section: Time-dependent Phonon Transport In the Transient Regimementioning

confidence: 99%

A brief review of thermal transport in mesoscopic systems from nonequilibrium Green's function approach

Xiong

2021

Preprint

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With the rapidly increasing integration density and power density in nanoscale electronic devices, the thermal management concerning heat generation and energy harvesting becomes quite crucial. Since phonon is the major heat carrier in semiconductors, thermal transport due to phonons in mesoscopic systems has attracted much attention. In quantum transport studies, the nonequilibrium Green's function (NEGF) method is a versatile and powerful tool that has been developed for several decades. In this review, we will discuss theoretical investigations of thermal transport using the NEGF approach from two aspects. For the aspect of phonon transport, the phonon NEGF method is briefly introduced and its applications on thermal transport in mesoscopic systems including onedimensional atomic chains, multi-terminal systems, and transient phonon transport are discussed. For the aspect of thermoelectric transport, the caloritronic effects in which the charge, spin, and valley degrees of freedom are manipulated by the temperature gradient are discussed. The timedependent thermoelectric behavior is also presented in the transient regime within the partitioned scheme based on the NEGF method.

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“…We can determine the energy current of the pumped electrons from the rate of change of the energy in each lead. The energy current [32][33][34][35] , traditionally known as the heat current, out of the left lead is…”

Section: Modeling the Devicementioning

confidence: 99%

Nonadiabatic particle and energy pump at strong system-reservoir coupling

Cuansing,

Wang,

Thingna

2020

Preprint

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We study the dynamics of electron and energy currents in a nonadiabatic pump. The pump is a quantum dot nanojunction with time-varying gate potential and tunnel couplings to the leads. The leads are unbiased and maintained at the same temperature and chemical potential. We find that synchronized variations of the gate and tunnel couplings can pump electrons and energy from the left to the right lead. Inspired by quantum heat engines, we devise a four-stroke operating protocol that can optimally pump energy and hence, we investigate energy transfer and the coefficient of performance of the device. We compare our device to a two-stroke pump and find that the latter's lower performance is due to the bi-directional flow of energy currents resulting in low net energy currents. The performance of our four-stroke pump can be improved, up to a point, by increasing the net energy carried by the pumped electrons through energy charging via the gate potential. This is achieved by increasing the durations of energy charging and discharging strokes in the pump's protocol. However, despite the large energy output for long charging and discharging strokes, the energy required to maintain the strokes become large too resulting in a stagnant pump performance. Our pump operates effectively only in the strong lead coupling regime and becomes a dud in the weak coupling regime due to the net output energy flowing in the reverse direction. We use nonequilibirum Green's functions techniques to calculate the currents and capture the effects of strong lead-channel coupling exactly while simultaneously incorporating three time-varying parameters. Results from our work could aid in the design of high-performance quantum pumps.

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Transient behavior of heat transport in a thermal switch

Cited by 37 publications

References 18 publications

Time-dependent Andreev bound states of a quantum dot coupled to two superconducting leads

Time-dependent Andreev bound states of a quantum dot coupled to two superconducting leads

A brief review of thermal transport in mesoscopic systems from nonequilibrium Green's function approach

Nonadiabatic particle and energy pump at strong system-reservoir coupling

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