Temperature and doping effects on the transport properties of SrIn2P2 Zintl compound

In this paper, we present and discuss temperature and doping effects on the electrical and thermal transport properties of SrIn2P2 Zintl phase along the [100] and [001] crystallographic directions. The calculations were performed by using the full-potential linearized augmented plane wave method in conjunction with Boltzmann's transport theory and Bardeen-Shockley's deformation potential with the carrier relaxation time and effective mass approximations. We calculated the band effective masses inside two energy windows of 125 meV; one above the fundamental conduction band minimum (FCBM) and the second below the valence band maximum (VBM). The calculated band effective masses exhibit a noticeable anisotropy and demonstrate that the n-type SrIn2P2 transport properties are better than those of the p-type one over the considered charge-carrier concentration range at room-, intermediate- and high-temperature, due to the proximity of the secondary conduction band minimums to the FCBM (similar to 58 meV). The n-type SrIn2P2 has a considerable Seebeck coefficient (429 mu V/K), an extremely low electrical resistivity (0.90 m Omega cm), and a relatively small lattice thermal conductivity (1.12 Wm(-1) K-1), which yield a figure of merit ZT of 0.87 for an electron concentration of 3.0 x 10(19) cm(-3) at 900 K. These results make SrIn2P2 a hopeful n-type thermoelectric material if we can further reduce its lattice thermal conductivity. (C) 2019 Elsevier B.V. All rights reserved.