Structural, Electronic, Optical and Elastic Characteristics of Cubic Perovskites TlXBr3 (X = Cu, Ag): A First Principles Calculations

Within the framework of density function theory (DFT), the structural, electronic, optical, and mechanical properties of cubic perovskites TlXBr3 (X = Cu, Ag) are investigated using WIEN2K code. The optimized equilibrium lattice parameters of the studied compounds are calculated and found to be 5.10 & Aring; and 5.42 & Aring; for TlCuBr3 and TlAgBr3, respectively. Formation energy is calculated to study the thermodynamic stability. To conform the dynamic stability, we also calculated the phonon dispersion curve. The phonon calculation indicates that both materials are dynamically stable. The calculations of elastic properties indicates that TlCuBr3 and TlAgBr3 compounds exhibit ductile nature, with anisotropic behaviors. Moreover, compounds demonstrate resistance to plastic deformation, attributes to their high G. The examination of electronic band structures and density of states (DOS) indicates that both materials have metallic nature. Moreover, the optical properties are calculated in the energy range of 0-20 eV to explore the potential of the studied materials for optoelectronic applications. The static refractive index values are found to be approximately 2.2 and 3.57 for TlCuBr3 and TlAgBr3 compounds respectively. It was observed that n(omega), and alpha(omega) exhibit analogous characteristics to epsilon(1) (omega), epsilon(2) (omega) and sigma (omega), respectively. These results provide understanding regarding the structural stability, mechanical behavior, electrical nature, and optical response of TlXBr3 (X = Cu, Ag) compounds, enhancing our knowledge of their unique features.