DFT Analysis of Transition Metal (TM) Substitutions on Cu-Based Chalcogenides: Structural, Electronic, and Thermophysical Properties for Interface Thermal Performance and Energy

The current investigation employs first-principles DFT (density functional theory) calculations to examine the influence of transition metal replacements on the structural, thermodynamic, and thermoelectric properties of Cu-based chalcogenides TMCu₃Se₄ (TM = Nb/Ta/V). The PBE-generalized gradient approximation (GGA) model is utilized to compute the fundamental properties of Cu-based chalcogenides under study. A thorough examination of the energy band structures indicates that these chalcogenides are semiconductor compounds with indirect energy bandgaps. We can infer from the calculated energy band structures that the bandgap values are 1.67, 1.77, and 1.05 eV for NbCu₃Se₄, TaCu₃Se₄, and VCu₃Se₄, respectively. The ${\mathrm{ZT}}_e$ values for NbCu₃Se₄, TaCu₃Se₄, and VCu₃Se₄ are 0.661, 0.998, and 0.996, respectively. These values make them highly appropriate for usage in thermoelectric (TE) devices. The thermoelectric characteristics of pyrochlore oxides TMCu₃Se₄ (TM = Nb/Ta/V) suggest that these materials have promising potential for energy-related applications. The analyzed thermodynamic properties demonstrate that the Cu0based chalcogenide materials TMCu₃Se₄ (TM = Nb/Ta/V) exhibit a notable level of thermal stability.