Exploring the Mechanical, Electronic, and Optical Properties of Gallium Based LmGaAs 2 (Lm = In, Eu, Ta) Chalcopyrites Implications for Photovoltaic Applications: An ab Initio DFT Study

In this study, we present the findings of a comprehensive investigation using first-principles methods to analyze the physical characteristics of the structural, electronic, optical, and elastic properties of the LmGaAs 2 (Lm = In, Eu, Ta) chalcopyrites. The calculated equilibrium parameters exhibit a high level of agreement with the experimental counterparts that are currently available, thereby providing evidence of the accuracy of the outcomes that were reported. The elastic properties, such as bulk modulus, shear modulus, Young’s modulus, and Poisson’s ratio, have been derived related to mechanical stability and anisotropic sound velocities. Based on the examination of the energy band dispersions, it has been determined that the investigated compounds exhibit semiconductor properties. These compounds possess direct band gaps within the 1.4–2.0 eV range, specifically positioned within the visible spectrum. The determination of the origins of the electronic states that make up the energy bands is achieved through the utilization of the Partial Density of States diagrams. Frequency-dependent linear optical parameters are calculated within an energy range of 0 to 14 eV for investigated chalcopyrites for both spin channels of compounds. The large value of birefringence in a wide frequency range ensures phase-matching capabilities. The materials exhibit potential sources for solar cells and LED applications in the optoelectronic industry.