First-principles investigation of pressure-induced structural, electronic, and thermoelectric properties in CoSb 3−x A x compounds (A = Ge, Se , Te )

The enhancement of thermoelectric properties in CoS b 3 through atom substitution and hydrostatic pressure application is a promising avenue. Herein, we conducted a comprehensive theoretical investigation into the structural, electronic, and thermoelectric characteristics of CoS b 3 − x A x (A = Ge, Se, Te; x = 0.125, 0.250) using density functional theory coupled with Boltzmann transport theory. By subjecting the system to pressures ranging from 0 to 20 GPa and substituting Sb atoms, we evaluated the enthalpy of formation to predict stability, with CoS b 2.875 T e 0.125 exhibiting superior stability under 20 GPa. The bandgap of doped compounds is direct, ranging from 0.33 to 0.56 eV along the Γ point, and was calculated to elucidate electronic properties. Additionally, employing the Slack model, we computed lattice thermal conductivity based on elastic constants to provide a comprehensive analysis of thermoelectric efficiency. Remarkably, our study not only highlights the effect of hydrostatic pressure on structural and electronic properties but also reveals a beneficial impact on increasing Z T values to 2.77 for CoS b 2.750 G e 0.250 at 800 K and 20 GPa, indicating predominantly p -type behavior. © 2024 Author(s).