Thermoelectric efficiency of topological insulators in a magnetic field

TL;DR

This paper investigates how magnetic fields and engineered hole densities in topological insulators can significantly enhance thermoelectric efficiency, with potential applications in nanoscale heat management.

Contribution

It demonstrates that high hole density and magnetic field tuning can greatly improve thermoelectric performance in topological insulators.

Findings

High ZT achievable with dense holes and magnetic field control

Magnetic field induces a tunable subgap in surface states

ZT values can exceed 1 under optimal conditions

Abstract

We study the thermoelectric properties of three-dimensional topological insulators in magnetic fields with many holes (or pores) in the bulk. We find that at high density of these holes in the transport direction the thermoelectric figure of merit, ZT, can be large due to the contribution of the topologically protected conducting surfaces and the suppressed phonon thermal conductivity. By applying an external magnetic field a subgap can be induced in the surface states spectrum. We show that the thermoelectric efficiency can be controlled by this tunable subgap leading to the values of ZT much greater than 1. Such high values of ZT for reasonable system parameters and its tunability by magnetic field make this system a strong candidate for applications in heat management of nanodevices, especially at low temperatures.