Abstract
Two-dimensional materials are considerably operated across various research areas including photovoltaics, semiconductors, electrodes, and medicine. New improvements in top-down and bottom-up synthetic techniques have made it possible to create 2D crystals with precise and distinctive optical characteristics. The optical properties of solids are a meaningful issue in both essential analysis and industrial employment. Comprehend-ing these properties has significant implications both technologically and fundamentally. In this direction, we analyze the electronic and optical properties like absorption, conductivity, reflectivity index, and dielectric function of 2D Ti4GaPbX2 (X = C or N) materials. The phonon dispersion curve of these layers showed no unstable phonon modes, demonstrating that these 2D monolayers are dynamically stable. Additionally, we have received the structures, i.e., Ti4GaPbC2 and Ti4GaPbN2 are dynamically stable, using DFT-AIMD. Our BS and TDOS have shown that these two-dimensional quaternary perovskites are metals. The second-order elastic constants of 2D Ti4GaPbC2 and Ti4GaPbN2 are also estimated. According to our GGA-PBE calculations, when the frequency of the light emitted is greater than the resonance frequencies (35.00 eV), the 2D Ti4GaPbC2 monolayer becomes transparent. While, when the incident light rate is greater than the plasma frequency similar to 10.00 eV, Ti4GaPbC2 becomes transparent. We also reported that these films have an excellent absorption coefficient in the similar to 0.00-60.00 eV area. It is worth noting that as the C atoms shift to N atoms, the plasma frequency rises.