Computational and Experimental Thermoelectric Properties of YCuSb 2

Abstract

High‐performance thermoelectric materials are vital to the transition toward clean energy technologies and require a unique combination of electrical and thermal properties. While those properties are often strongly intertwined in conventional materials, topological materials can decouple the electrical and thermal properties, providing an avenue to independently optimize each property. In this study, the topological insulator YCuSb 2 and Te‐doped derivatives were synthesized, characterized, and their thermoelectric properties were measured. Low electrical resistivity (77–355 µΩ·cm) with relatively low lattice thermal conductivity (<8 W m −1 K −1 ) was found at 300 K. The thermal conductivity is mostly dominated by the electrical contribution. Despite these favorable transport characteristics, a low Seebeck coefficient (<8 µV K −1 ) limits the overall thermoelectric performance of YCuSb 2 . Comparison of the experimental results with electronic structure calculations indicates that the nearly constant density of states near the Fermi level is responsible for the low thermoelectric figure of merit (∼0.001 at 300 K). These findings identify the electronic structure near the Fermi level as the primary limitation to enhancing the thermoelectric performance and therefore, band‐structure engineering might be a promising strategy for improving the thermoelectric properties of YCuSb 2 ‐based materials.