Screening for new thermoelectric material: A semiconducting TaS3 with nanoporous structure

Transition-metal sulfides, such as 1T-and 2H-TaS2, are attracting considerable interest in modern condensed matter physics for their diverse behaviors of the Mott state, peculiar charge-density-wave phase and superconductivity. The intrinsically low thermal conductivities along the cross-plane direc-tion can advantage the potential high thermoelectric performance; yet, their insignificant power factors severely hampered the practical applications as thermoelectric devices. In this perspective, we herein present a new semiconducting phase in TaS3 with the space group C2/m predicted by the swarm -intelligence structure-searching method. The C2/m-TaS3 phase exhibits anisotropic multivalley band dispersions, which is beneficial for electronic transport. Meanwhile, the unique structure within nano -pores leads to strong anharmonic scattering, significantly reducing the lattice thermal conductivity. As a result, the calculated figure of merit ZT can reach up to 1.68 and 1.57 at 800 K for p- and n-type, respectively that is comparable with conventional thermoelectric materials (e.g. PbTe, Bi2Te3). Therefore, our calculation reveals that the C2/m-TaS3 phase can be a potential high-performance candidate as non-toxic and eco-friendly thermoelectrics, and will stimulate further experimental exploration for under-standing and tailoring thermoelectric capability in related transition-metal sulfides. (C) 2022 The Chinese Ceramic Society. Production and hosting by Elsevier B.V.

Automated summary

This article introduces a new semiconducting phase in TaS3, called the C2/m phase, which has beneficial multivalley band dispersions for electronic transport and a unique nano-pore structure that reduces thermal conductivity. It shows potential high-performance thermoelectric capability.