Performance analysis of an interacting quantum dot thermoelectric setup

Muralidharan, Bhaskaran and Grifoni, Milena (2012) Performance analysis of an interacting quantum dot thermoelectric setup. PHYSICAL REVIEW B, 85 (15): 155423. ISSN 1098-0121,

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Abstract

In the absence of phonon contribution, a weakly coupled single orbital noninteracting quantum dot thermoelectric setup is known to operate reversibly as a Carnot engine. This reversible operation, however, occurs only in the ideal case of vanishing coupling to the contacts, wherein the transmission function is delta shaped, and under open-circuit conditions, where no electrical power is extracted. In this paper, we delve into the thermoelectric performance of quantum dot systems by analyzing the power output and efficiency directly evaluated from the nonequilibrium electric and energy currents across them. In the case of interacting quantum dots, the nonequilibrium currents in the limit of weak coupling to the contacts are evaluated using the Pauli master equation approach. The following fundamental aspects of the thermoelectric operation of a quantum dot setup are discussed in detail: (a) With a finite coupling to the contacts, a thermoelectric setup always operates irreversibly under open-circuit conditions, with a zero efficiency. (b) Operation at a peak efficiency close to the Carnot value is possible under a finite power operation. In the noninteracting single orbital case, the peak efficiency approaches the Carnot value as the coupling to the contacts becomes smaller. In the interacting case, this trend depends nontrivially on the interaction parameter U. (c) The evaluated trends of the maximum efficiency derived from the nonequilibrium currents deviate considerably from the conventional figure of merit zT-based results. Finally, we also analyze the interacting quantum dot setup for thermoelectric operation at maximum power output.

Item Type: Article
Uncontrolled Keywords: MAXIMUM POWER; EFFICIENCY; FIGURE; MERIT;
Subjects: 500 Science > 530 Physics
Divisions: Physics > Institute of Theroretical Physics > Chair Professor Grifoni > Group Milena Grifoni
Depositing User: Dr. Gernot Deinzer
Date Deposited: 15 May 2020 04:49
Last Modified: 15 May 2020 04:49
URI: https://pred.uni-regensburg.de/id/eprint/18895

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