Effect of Thermoelectric Cooling in Nanoscale Junctions

TL;DR

This paper investigates an atomic-scale thermoelectric refrigerator, revealing that quantum effects and minimized local heating enable higher efficiency and cooling performance than traditional bulk thermoelectric systems.

Contribution

It introduces a first-principles study of an atomic-sized thermoelectric cooler, highlighting quantum effects and local heating suppression as key to improved efficiency.

Findings

Atomic refrigerator operates within a narrow voltage range.

Higher efficiency than bulk thermoelectric devices with same ZT.

Quantum size effects enhance electron cooling performance.

Abstract

We propose a thermoelectric cooling device based on an atomic-sized junction. Using first-principles approaches, we investigate the working conditions and the coefficient of performance (COP) of an atomic-scale electronic refrigerator where the effects of phonon's thermal current and local heating are included. It is observed that the functioning of the thermoelectric nano-refrigerator is restricted to a narrow range of driving voltages. Compared with the bulk thermoelectric system with the overwhelmingly irreversible Joule heating, the 4-Al atomic refrigerator has a higher efficiency than a bulk thermoelectric refrigerator with the same $ZT$ due to suppressed local heating via the quasi-ballistic electron transport and small driving voltages. Quantum nature due to the size minimization offered by atomic-level control of properties facilitates electron cooling beyond the expectation of the conventional thermoelectric device theory.