Hole-doped cobalt-based Heusler phases as prospective high-performance high-temperature thermoelectrics

TL;DR

This study uses first-principles calculations to identify hole-doped cobalt-based Heusler phases with significantly improved thermoelectric performance at high temperatures, highlighting CoWIn as particularly promising.

Contribution

It demonstrates that p-type doping of specific cobalt-based Heusler phases can substantially enhance thermoelectric efficiency, with lower thermal conductivity and higher figure of merit than CoTiSb.

Findings

All studied systems have lower thermal conductivity than CoTiSb.

CoMoIn and CoWIn exhibit nearly three times lower thermal conductivity.

Estimated figure of merit is higher than CoTiSb, especially for CoWIn.

Abstract

Materials design based on first-principles electronic calculations has proven a fruitful strategy to identify new thermoelectric materials with a favorable figure of merit. Recent electronic structure calculations predict that in cobalt-based half-Heusler systems a power factor higher than in CoTiSb can be achieved upon p-type doping of CoVSn, CoNbSn, CoTaSn, CoMoIn, and CoWIn. Here, using a first-principles approach and semi-classical Boltzmann transport theory, we investigate the electrical and thermal transport properties of these materials. The calculated thermal conductivity at room temperature of all the systems is lower than that of CoTiSb, with CoMoIn and CoWIn having an almost 3-fold lower thermal conductivity than CoTiSb. We also provide conservative estimates of the figure of merit for these systems which all turn out to be higher than in CoTiSb and to have a maximum value for CoWIn.