Optimization of a three-terminal non-linear heat nano-engine

TL;DR

This paper investigates a three-terminal nano-engine where quantum dots enable independent control of heat and charge flows, revealing that non-equilibrium effects influence optimal parameters but not maximum power or efficiency.

Contribution

It introduces a novel three-terminal heat nano-engine design with quantum dots that allows independent control of heat and charge currents, analyzing non-equilibrium effects on performance.

Findings

Non-equilibrium screening alters optimal system parameters.

Maximum power and efficiency remain unaffected by non-equilibrium effects.

Heat and charge currents flow in mutually perpendicular directions.

Abstract

Charge and heat transport in nano-structures is dominated by non-equilibrium effects which strongly influence their behaviour. These effects are studied in a setup consisting of three external leads, one of which is considered as a heat reservoir and is tunnel-coupled to two cold electrodes via two independently controlled quantum dots. The energy flow from the hot electrode together with energy filtering provided by quantum dots leads to a voltage bias between the cold electrodes. The heat and charge currents in the device effectively flow in mutually perpendicular directions, allowing for their independent control. The non-equilibrium screening changes the values of the system parameters needed for its optimal performance but leaves the maximal output power and efficiency unchanged. Our results are important from the theoretical point of view as well as for the practical implementation and the control of the proposed heat engine.