First-principles investigation of structural, electronic, optical, elastic, and thermoelectric properties of cubic francifluorite perovskites FrXF₃ (X = Si, Ge, and Sn) for optoelectronic and thermoelectric applications

Abstract

This study presents the results of first-principles calculations based on Density Functional Theory (DFT) implemented in the Wien2k code, investigating the properties of FrXF3 compounds where B represents Si, Ge, and Sn. Various exchange-correlation functionals, including Generalized Gradient Approximation (GGA) with Perdew-Burke-Ernzerhof (GGA-PBE), Perdew-Burke-Ernzerhof revised for Solids (GGA-PBEsol), Wu-Cohen exchange (GGA-WC), and Modified Becke-Johnson potential (TB-mBJ), were employed to comprehensively analyze the structural, electronic, optical, elastic, and thermoelectric characteristics of these compounds. The analysis of band structures and density of states revealed that all three compounds exhibit semiconducting behavior with direct band gaps, and the band gaps decrease as we move from Si to Sn. The calculated optical properties indicate strong optical responses in the visible to ultraviolet energy range, suggesting potential applications in optoelectronics. Furthermore, the study evaluated the thermoelectric parameters, including thermal and electrical conductivity, power factor, Seebeck coefficient, and figure of merit. The results demonstrate that the FrXF3 compounds possess remarkable thermoelectric potential, indicating their suitability for thermoelectric applications. Overall, this comprehensive investigation provides valuable insights into the structural, electronic, optical, elastic, and thermoelectric properties of FrXF3 compounds, highlighting their potential for various technological applications, particularly in the field of optoelectronics and thermoelectric devices.