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

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 Å and 5.42 Å 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(ω), and α(ω) exhibit analogous characteristics to ε1 (ω), ε2 (ω) and σ (ω),
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.