Zintl Phase BaAgSb: Low Thermal Conductivity and High Performance Thermoelectric Material in Ab Initio CalculationSupported by the National Key R&D Program of China (Grant Nos. 2016YFA0401503 and 2017YFA0403700), the National Natural Science Foundation of China (Grant Nos. 11675255, U1932220, 11675195, and U1932220), the Key Research Program of Frontier Sciences, CAS (Grant No. 292016YQYKXJ00135), and the Program of State Key Laboratory

Abstract

Thermoelectric materials are critical parts in thermal electric devices. Here, Zintl phase BaAgSb in space group of P63/mmc is reported as a promising thermoelectric material in density function theory. The anisotropic lattice thermal conductivity and phonon transport properties are investigated in theory. The strong phonon-phonon scattering in BaAgSb exhibits ultra-low lattice thermal conductivity of 0.59 W⋅m−1⋅K−1 along c-axis at 800 K, and high thermoelectric performance ZT = 0.94 at 400 K. The mix of covalent and ionic bond supports high carrier mobility and low thermal conductivity. The unusual features make BaAgSb a potential thermoelectric material.