First-Principles Study on the Thermoelectric Properties of FeAsS

[Image: see text] The electronic structure and thermoelectric properties of FeAsS are studied by the first-principles and the Boltzmann transport theory. The results show that FeAsS is a semiconductor with an indirect band gap of 0.73 eV. The dimensionless figure of merit (ZT) has obvious anisotropy, ZT value along the x- and y-directions is significantly larger than that along the z-direction, and p-type doping has better thermoelectric performance than n-type doping. The largest ZT value can reach 0.84, which is for p-type doping along the x-direction. The lattice thermal conductivity is extremely low, which is smaller than 1 W m(–1) K(–1). The results show that FeAsS is a promising candidate for thermoelectric applications.