Microwave-mediated heat transport through a quantum dot

TL;DR

This paper investigates how microwave fields influence heat and charge transport in a quantum dot system, revealing photon-induced effects and unconventional heat flow behaviors that could impact thermoelectric device design.

Contribution

It introduces a detailed theoretical analysis of microwave effects on thermoelectric properties in quantum dots, including novel heat flow phenomena when microwaves are applied selectively.

Findings

Microwave application on the QD reduces thermoelectric peaks and creates photon-induced peaks.

Applying microwaves to only one lead causes heat to flow from dark to bright lead, regardless of thermal gradient.

Microwaves can alter both the magnitude and sign of electrically induced by temperature gradients.

Abstract

The thermoelectric effect in a quantum dot (QD) attached to two leads in the presence of microwave fields is studied by using the Keldysh nonequilibrium Green function technique. When the microwave is applied only on the QD and in the linear-response regime, the main peaks in the thermoelectric figure of merit and the thermopower are found to decrease, with the emergence of a set of photon-induced peaks. Under this condition the microwave field can not generate heat current or electrical bias voltage. Surprisingly, when the microwave field is applied only to one (bright) lead and not to the other (dark) lead or the QD, heat flows mostly from the dark to the bright lead, almost irrespectively to the direction of the thermal gradient. We attribute this effect to microwave-induced opening of additional transport channels below the Fermi energy. The microwave field can change both the magnitude and the sign of the electrical bias voltage induced by the temperature gradient.