Tuning thermoelectric power factor by crystal-field and spin-orbit couplings in Kondo lattice materials

TL;DR

This paper investigates how tuning crystal-field and spin-orbit couplings in Kondo lattice materials can enhance thermoelectric efficiency at low temperatures, providing a framework for designing better thermoelectric devices.

Contribution

It introduces a novel approach to improve low-temperature thermoelectric performance by manipulating electronic interactions in Kondo insulators.

Findings

Correlation effects can significantly enhance thermoelectric figure of merit (ZT).

Tuning crystal-field and spin-orbit couplings influences energy gaps and transport properties.

Framework for designing more efficient low-temperature thermoelectric materials.

Abstract

We study thermoelectric transport at low temperatures in correlated Kondo insulators, motivated by the recent observation of a high thermoelectric figure of merit(ZT) in $FeSb_2$ at $T \sim 10 K$. Even at room temperature, correlations have the potential to lead to high ZT, as in $YbAl_3$, one of the most widely used thermoelectric metals. At low temperature correlation effects are especially worthy of study because fixed band structures are unlikely to give rise to the very small energy gaps $E_g \sim 5 kT$ necessary for a weakly correlated material to function efficiently at low temperature. We explore the possibility of improving the thermoelectric properties of correlated Kondo insulators through tuning of crystal field and spin-orbit coupling and present a framework to design more efficient low-temperature thermoelectrics based on our results.