Helical thermoelectrics and refrigeration

TL;DR

This paper investigates the thermoelectric properties of three-terminal quantum spin Hall samples, highlighting their ability to efficiently generate charge and spin heat currents, and their potential as versatile heat engines and refrigerators.

Contribution

It introduces the concept of helical thermoelectrics in QSH systems, demonstrating their dual functionality as charge/spin heat engines and refrigerators with preserved TR symmetry.

Findings

Helical QSH systems generate large charge power efficiently.

They can operate as both heat engines and refrigerators.

Preservation of TR symmetry enables dual charge/spin functionalities.

Abstract

The thermoelectric properties of a three terminal quantum spin Hall (QSH) sample are examined. Inherent helicity of the QSH sample helps to generate a large charge power efficiently. Along with charge the system can be designed to work as a highly efficient spin heat engine too. The advantage of a helical over a chiral sample is that, while a multiterminal quantum Hall sample can only work as a quantum heat engine due to broken time reversal(TR) symmetry, a multiterminal QSH system can work effectively both as a charge/spin heat engine as well as a charge/spin refrigerator as TR symmetry is preserved.