Separation of heat and charge currents for boosted thermoelectric conversion

TL;DR

This paper introduces a multi-terminal device design that achieves extreme separation of heat and charge currents, enabling independent control and significantly improved thermoelectric efficiency at low temperatures.

Contribution

It proposes a novel multi-terminal device architecture with heat-charge current separation, enhancing thermoelectric performance beyond traditional two-terminal systems.

Findings

Heat-charge current separation regime enhances thermoelectric efficiency.

Power factor and ZT are significantly increased in the proposed setup.

Results confirmed in a three quantum dot system.

Abstract

In a multi-terminal device the (electronic) heat and charge currents can follow different paths. In this paper we introduce and analyse a class of multi-terminal devices where this property is pushed to its extreme limits, with charge $and$ heat currents flowing in different reservoirs. After introducing the main characteristics of such $heat-charge$ $current$ $separation$ regime we show how to realise it in a multi-terminal device with normal and superconducting leads. We demonstrate that this regime allows to control independently heat and charge flows and to greatly enhance thermoelectric performances at low temperatures. We analyse in details a three-terminal setup involving a superconducting lead, a normal lead and a voltage probe. For a generic scattering region we show that in the regime of heat-charge current separation both the power factor and the figure of merit $ZT$ are highly increased with respect to a standard two-terminal system. These results are confirmed for the specific case of a system consisting of three coupled quantum dots.