First principle method for studying thermoelectric properties of anti-perovskite Ba3SiO and Ca3SiO compounds

Abstract

Thermoelectric materials, which utilize a temperature gradient to convert heat energy into electrical energy, hold immense promise for power generation. The efficiency of such compounds is mainly measured by their figure of merit (ZT), which indicates their efficiency to convert heat energy to electrical energy. This study investigated the potential of anti-perovskite Ba₃SiO and Ca₃SiO compounds as thermoelectric materials. The Boltzmann transport equation (BTE) was utilized using the BoltzTraP code to evaluate the transport and thermoelectric properties of Ba₃SiO and Ca₃SiO compounds. The electronic properties including, the band structure and density of states (DOS) were computed using CASTEP code using the generalized gradient approximation with the Perdew-Burke-Ernzerhof (GGA-PBE) functional. Results showed that both Ba₃SiO and Ca₃SiO are direct band gap semiconductor materials at the Γ - Γ k-points with band gaps values of 0.44 eV for Ba₃SiO and 0.11 eV for Ca₃SiO. In addition, we found that the figure of merit at room temperature was determined to be higher for Ca₃SiO compared to Ba₃SiO, with values of 2.50  10^-2   and 9.66  10^-4, respectively. This indicates that substituting of X cation from Ba to Ca in the X₃SiO compound enhances in the thermoelectric performance.