Computational analysis of AlXSnSe4 (X = Ag and Cu) quaternary compounds: Uncovering first-principles insights into electronic structure, optical, and thermoelectric nature

Employing the recognized density functional theory, here we studied the multifaceted interactions of the structural, electrical, optical, and transport nature of new direct band gap AlXSnSe4 (X = Ag and Cu) quaternary materials. Significant band overlap between the electronic states of Tot-Ag and Tot-Se suggests that these two systems have strong bonding properties. The minima and maxima of the conduction band and valence band are located at the high symmetry Gamma-point in the first Brillouin zone which suggests a good behavior for optoelectronic devices. There exists a clear correlation between the dipole inter-band transition probability and the value of the real component of the dielectric constant. The highest absorption peaks are found in the ultraviolet spectrum, indicating that these materials are effective absorbers of the low- and medium-UV radiation. The high reflectivity values for both materials varied between 4.0 eV and 13.5 eV as photon energy increased. The considered materials are also suitable to be used in thermoelectric applications, that is confirmed from their significant and notable thermoelectric features.