Designing a highly efficient graphene quantum spin heat engine

TL;DR

This paper proposes a highly efficient graphene-based quantum spin heat engine utilizing spin polarized ballistic modes, demonstrating large thermoelectric efficiency and the ability to transport pure spin currents without charge flow.

Contribution

It introduces a novel graphene quantum spin heat engine design with superior efficiency and compares its performance to quantum spin Hall heat engines, highlighting its potential for spintronic applications.

Findings

Achieves high thermoelectric efficiency for charge and spin variants.

Can nearly match the performance of quantum spin Hall heat engines.

Capable of transporting pure spin currents without charge flow.

Abstract

We design a quantum spin heat engine using spin polarized ballistic modes generated in a strained graphene monolayer doped with a magnetic impurity. We observe remarkably large efficiency and large thermoelectric figure of merit both for the charge as well as spin variants of the quantum heat engine. This suggests the use of this device as a highly efficient quantum heat engine for charge as well as spin-based transport. Further, a comparison is drawn between the device characteristics of a graphene spin heat engine against a quantum spin Hall heat engine. The reason being edge modes because of their origin should give much better performance. In this respect, we observe our graphene-based spin heat engine can almost match the performance characteristics of a quantum spin Hall heat engine. Finally, we show that a pure spin current can be transported in our device in absence of any charge current.