Thermoelectric transport in torsional strained Weyl semimetals

TL;DR

This paper investigates how torsional strain and magnetic fields influence thermoelectric transport in Weyl semimetals, providing analytical formulas and suggesting ways to optimize their thermoelectric efficiency.

Contribution

It extends previous work by deriving exact analytical expressions for thermoelectric coefficients in strained Weyl semimetals under magnetic fields.

Findings

Thermoelectric coefficients can be tuned by magnetic field and strain.

Potential for high thermoelectric figure of merit.

Analytical expressions for heat current and conductance.

Abstract

In a recent paper [R. Soto-Garrido and E. Mu\~noz, J. Phys. Condens. Matter 30, 195302 (2018)], we studied the electronic transport properties in Weyl semimetals (WSMs) submitted to the combined effects of torsional mechanical strain and magnetic field, showing that this configuration induces a node-polarization effect on the current that can be used to measure the torsion angle from transmission experiments. In this article, we extend our previous work to study thermoelectric transport in WSMs under torsional strain and an external magnetic field. Our analysis involves only the electronic contribution to the transport coefficients, and it is thus valid at low temperatures where the phonon contribution is negligible. We provide exact analytical expressions for the scattering cross section and the transmitted heat current, in order to calculate the thermal conductance and the Seebeck coefficient under this configuration. Our results suggest that thermoelectric transport coefficients in these materials can be engineered by appropriately tuning the magnitude of the magnetic field, torsional strain, and the applied bias or thermal gradient, leading to a potentially very high figure of merit.