Strain‐induced effects on thermoelectric performance of layered LaCuOSe

Abstract

In this study, the strain‐induced effects on thermal and electrical transport properties of LaCuOSe are studied by combining first‐principles calculations with semi‐classical Boltzmann transport theory. The results show that external strain affects the crystal and electronic structures of LaCuOSe significantly. It is interesting to find that the electrical conductivity of n‐type LaCuOSe is improved by the tensile strain. In addition, the tensile strain also has positive effects on the Seebeck coefficient of p‐type doped LaCuOSe. Consequently, the power factor of p‐type doped LaCuOSe is enhanced by 18.2% under 10% tensile strain at 800 K. However, due to the obviously affected mechanical properties of LaCuOSe under external strain, the decreased Grüneisen constant and reduced Debye temperatures are resulted, and the lattice thermal conductivity of LaCuOSe at 300 K increases from 2.91 to 5.95 Wm/K with the tensile strain increasing from 0% to 10%. The sharply increased thermal conductivity finally results in the optimal ZT value of 0.076 and 0.417 for ideal p‐ and n‐type LaCuOSe at 800 K being reduced to 0.048 and 0.286 under 10% tensile strain, respectively. These results suggest that the thermoelectrical properties of LaCuOSe need to be further improved for its application under stress.