Evaluating Thermoelectric Properties of BaTiS₃ by Density Functional Theory

Authors

Tula R. Paudel, University of Nebraska-LincolnFollow
Evgeny Y. Tsymbal, University of Nebraska-LincolnFollow

ORCID IDs

Tsymbal http://orcid.org/0000-0002-6728-5481

Paudel https://orcid.org/0000-0002-9952-9435

Document Type

Article

Date of this Version

2020

Citation

ACS Omega (2020) 5: 12,385−12,390

doi: 10.1021/acsomega.0c01139

Comments

Copyright 2020, the authors. Open access

License: ACS Author Choice

Abstract

BaTiS₃ is a semiconductor with a small bandgap of ∼0.5 eV and strong transport anisotropy caused primarily by structural anisotropy; it contains well-separated octahedral columns along the [0001] direction and low lattice thermal conductivity, appealing for thermoelectric applications. Here, we evaluate the prospect of BaTiS₃ as a thermoelectric material by using the linearized electron and phonon Boltzmann transport theory based on the firstprinciples density functional band structure calculations. We find sizable values of the key thermoelectric parameters, such as the maximum power factor PF = 928 μWK⁻² and the maximum figure of merit ZT = 0.48 for an electron-doped sample and PF = 74 μW K⁻² and ZT = 0.17 for a hole-doped sample at room temperature, and a small doping level of ±0.25e per unit cell. The increase in temperature yields an increase in both the power factor and the figure of merit, reaching large values of PF = 3078 μWK⁻² and ZT = 0.77 for the electron-doped sample and PF = 650 μW K⁻² and ZT = 0.62 for the hole-doped sample at 800 K. Our results elucidate the promise of BaTiS₃ as a material for the thermoelectric power generator.