The thermal and electrical transport properties of layered LaCuOSe under high pressure

In this study, first-principles calculations combined with semi-classical Boltzmann transport theory are carried out to study the thermal and electrical transport properties of LaCuOSe under high pressure. The results show that the Seebeck coefficient of LaCuOSe decreases significantly as the pressure rises, because of significant changes in crystal and electronic structures. Meanwhile, the electrical conductivity is also declined by high pressure. Additionally, the external pressure leads to decreased lattice parameters, high phonon vibrational frequency and enhanced heat transport. Therefore, the lattice thermal conductivity of LaCuOSe at 900 K increases with increasing pressure. As a result, the optimal figure of merit of LaCuOSe at 900 K is reduced from 0.99 (3.34) to 0.06 (0.35) along the a-axis (c-axis) as the pressure changes from 0 to 10 GPa. These results suggest that high hydrostatic pressure has negative effects on the thermoelectric properties of the layered LaCuOSe. (C) 2020 Elsevier B.V. All rights reserved.