Quantum control of nonlinear thermoelectricity at the nanoscale

Taniguchi, Nobuhiko

doi:10.1103/physrevb.101.115404

Cited by 13 publications

(11 citation statements)

References 75 publications

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“…Kondo effect [22,23,28,50,51], energy spectrum of the QD [40,43,48], electron-phonon interactions [44,54,55], and the Fano effect [56][57][58] on the thermoelectric properties of QD heat engines has also been investigated in the linear and non-linear regime. Krawiec et al [41] studied the influence of asymmetric dot-reservoir coupling (Γ L = Γ R ) on thermoelectric properties and showed that in the linear regime, the thermopower S and figure of merit ZT are unaffected by asymmetry.…”

Section: Introductionmentioning

confidence: 99%

A Strongly Correlated Quantum-Dot Heat Engine with Optimal Performance: An Non-equilibrium Green's function Approach

Verma¹,

Ajay²

2022

Preprint

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We present an analytical study of a strongly correlated quantum dot-based thermoelectric particle-exchange heat engine for both finite and infinite on-dot Coulomb interaction. Employing Keldysh's non-equilibrium Green's function formalism for different decoupling schemes in the equation of motion, we have analyzed the thermoelectric properties within the non-linear transport regime. As the simplest mean-field approximation is insufficient for analyzing thermoelectric properties in the Coulomb blockade regime, one needs to employ a higher-order approximation to study strongly correlated QD-based heat engines. Therefore initially, we have used the Hubbard-I approximation to study the quantum dot level position ( d ), thermal gradient (∆T ), and on-dot Coulomb interaction (U ) dependence of the thermoelectric properties. Furthermore, as a natural extension, we have used an approximation beyond Hubbard-I in the infinite-U limit (strong on-dot Coulomb repulsion) to provide additional insight into the operation of a more practical quantum dot heat engine. Within this infinite-U limit, we examine the role of the symmetric dot-reservoir tunneling (Γ) and external serial load resistance (R) in optimizing the performance of the strongly correlated quantum dot heat engine. Our infinite-U results show a good quantitative agreement with recent experimental data for a quantum dot coupled to two metallic reservoirs.

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Section: Introductionmentioning

confidence: 99%

A Strongly Correlated Quantum-Dot Heat Engine with Optimal Performance: An Non-equilibrium Green's function Approach

Verma¹,

Ajay²

2022

Preprint

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“…Taking into account the special profile of Fano and hybrid resonances as well as its impact on the transport properties of bilayer graphene barrier structures, we can expect high values for the Seebeck coefficient, power factor and ZT . Actually, there are several reports in the literature in which is well-documented how Fano resonances enhance thermoelectricity 42 – 47 . The typical systems consist of quantum-dot interferometers, molecular junctions and chain junctions to mention a few.…”

Section: Introductionmentioning

confidence: 99%

Enhancement of the thermoelectric properties in bilayer graphene structures induced by Fano resonances

Briones-Torres

Pérez‐Álvarez

Molina-Valdovinos

et al. 2021

Sci Rep

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Fano resonances of bilayer graphene could be attractive for thermoelectric devices. The special profile presented by such resonances could significantly enhance the thermoelectric properties. In this work, we study the thermoelectric properties of bilayer graphene single and double barrier structures. The barrier structures are typically supported by a substrate and encapsulated by protecting layers, reducing considerably the phonon thermal transport. So, we will focus on the electronic contribution to the thermal transport. The charge carriers are described as massive chiral particles through an effective Dirac-like Hamiltonian. The Hybrid matrix method and the Landauer–Büttiker formalism are implemented to obtain the transmission, transport and thermoelectric properties. The temperature dependence of the Seebeck coefficient, the power factor, the figure of merit and the efficiency is analyzed for gapless single and double barriers. We find that the charge neutrality point and the system resonances shape the thermoelectric response. In the case of single barriers, the low-temperature thermoelectric response is dominated by the charge neutrality point, while the high-temperature response is determined by the Fano resonances. In the case of double barriers, Breit–Wigner resonances dominate the thermoelectric properties at low temperatures, while Fano and hybrid resonances become preponderant as the temperature rises. The values for the figure of merit are close to two for single barriers and above three for double barriers. The system resonances also allows us to optimize the output power and the efficiency at low and high temperatures. By computing the density of states, we also corroborate that the improvement of the thermoelectric properties is related to the accumulation of electron states. Our findings indicate that bilayer graphene barrier structures can be used to improve the response of thermoelectric devices.

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“…This confirms consistency between all methods at weak enough phonon coupling strength, and highlights the limitations of the WCME as the phonon coupling is increased. For all methods we employ counting statistics techniques [15,24,25,[44][45][46] to calculate the transport cumulants necessary to evaluate the thermoelectric power output, noise, and efficiency.…”

Section: Introductionmentioning

confidence: 99%

Strong coupling in thermoelectric nanojunctions: a reaction coordinate framework

McConnell,

Nazir

2021

Preprint

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We study a model of a thermoelectric nanojunction driven by vibrationally-assisted tunneling. We apply the reaction coordinate formalism to derive a master equation governing its thermoelectric performance beyond the weak electron-vibrational coupling limit. Employing full counting statistics we calculate the current flow, thermopower, associated noise, and efficiency without resorting to the weak vibrational coupling approximation. We demonstrate intricacies of the power-efficiencyprecision trade-off at strong coupling, showing that the three cannot be maximised simultaneously in our model. Finally, we emphasise the importance of capturing non-additivity when considering strong coupling and multiple environments, demonstrating that an additive treatment of the environments can violate the upper bound on thermoelectric efficiency imposed by Carnot.

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Quantum control of nonlinear thermoelectricity at the nanoscale

Cited by 13 publications

References 75 publications

A Strongly Correlated Quantum-Dot Heat Engine with Optimal Performance: An Non-equilibrium Green's function Approach

A Strongly Correlated Quantum-Dot Heat Engine with Optimal Performance: An Non-equilibrium Green's function Approach

Enhancement of the thermoelectric properties in bilayer graphene structures induced by Fano resonances

Strong coupling in thermoelectric nanojunctions: a reaction coordinate framework

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