Simultaneously optimizing the interdependent thermoelectric parameters in Ce(Ni$_{1-x}$Cu$_x$)$_2$Al$_3$

TL;DR

This study demonstrates that substituting Cu for Ni in CeNi$_2$Al$_3$ optimizes thermoelectric parameters simultaneously, leading to a notable figure of merit at cryogenic temperatures, highlighting a promising approach for thermoelectric materials.

Contribution

It reveals that electronic tuning via Cu substitution in CeNi$_2$Al$_3$ can optimize thermoelectric properties simultaneously, a novel strategy for Kondo compounds.

Findings

Achieved a $zT$ of 0.125 at 100 K

Electronic band changes are crucial for optimization

Proper tuning enhances thermoelectric performance

Abstract

Substitution of Cu for Ni in the Kondo lattice system CeNi$_2$Al$_3$ results in a simultaneous optimization of the three interdependent thermoelectric parameters: thermoelectric power, electrical and thermal conductivities, where the electronic change in conduction band induced by the extra electron of Cu is shown to be crucial. The obtained thermoelectric figure of merit $zT$ amounts to 0.125 at around 100 K, comparable to the best values known for Kondo compounds. The realization of ideal thermoelectric optimization in Ce(Ni$_{1-x}$Cu$_x$)$_2$Al$_3$ indicates that proper electronic tuning of Kondo compounds is a promising approach to efficient thermoelectric materials for cryogenic application.