Structural, Electronic, and Transport Properties of ATcO3 (A = Ag, Au, Cd): A First-Principles Study

Abstract

We computed the electronic and thermoelectric properties of ATcO₃ (A = Ag, Au, Cd) perovskites using Density Functional Theory (DFT). Employing the Perdew-Burke-Ernzerhof (PBE) functional within the Generalized Gradient Approximation (GGA), we confirmed the thermodynamic and thermal stability via the enthalpy of formation (ΔH) and ab-initio molecular dynamic (AIMD) simulations. The electronic properties indicate a metallic-like behavior with PBE and Modified Becke-Johnso (mBJ), owing to the higher contribution of the Ag/Au-d states at the Fermi level of AgTcO₃ and AuTcO₃. In CdTcO₃, Cd-s provides very little contribution at the Fermi level, resulting in lower conductivity compared to Ag- and Au-based perovskites. These differences lead to significant variations in their conductivity and, hence, the thermoelectric performance. Based on the Seebeck coefficient, it was observed that CdTcO₃ exhibits n-type behavior, while the Au- and Ag-based compounds show p-type nature. CdTcO₃ displayed a high value of the Figure of Merit (∼ 0.63), suggesting its potential as a good candidate material for n-type thermoelectric applications.