The electronic, optical, and vibrational properties of Ag3X (X = S, Se) with density functional theory

Abstract

Using ab initio first-principles calculations, we investigate the structural, electronic, optical, and vibrational properties of Silver Sulphide Ag3S and Selenide Ag3Se with nonlocal hybrids exchange-correlation functional. With our computational predictions, we manage to classify the material to be Fermi-Dirac semi-metal, rather than Weyl metal. Our calculated results show that the electronic band in between the Fermi-Dirac cone shifts downward when we replace the element Sulphide S with Selenide Se. The obtained optical results such as absorption coefficients and dielectric functions (conductivity, reflectivity, etc.) are similar for both Ag3S and Ag3Se. A high absorption coefficient of [Formula: see text] cm[Formula: see text] has been reported, and about 50% of light is reflected. In Raman spectra, the A[Formula: see text] managed to shift downward when replacing the element X, sulphide S with selenide Se, while the A[Formula: see text] shifts upward (to higher wavelength). The rotation and vibration of the bonding between atoms have also been explained. The calculated results of Silver-VI compounds provide useful information in the exploitation of more complicated structures.