Structural, elastic, thermodynamic and electronic properties of covellite, CuS

Abstract

Covellite, the CuS, is a unique compound owing to both superconducting and metallic behavior at different temperatures. We model and characterize the elastic, electronic and associated properties of the CuS launching the state-of-art first-principles calculations taking the exchange and correlation energy functionals based on the gradient generalized approximation and hybrid functionals. After settling the crystal structure, we find elastic constants and related mechanical constants. As the crystal satisfies the stability criterion, so we compute the sound velocity, Debye temperature and lower bound of the thermal conductivity also. The electronic bands dispersion and the density of states exhibit the metallic behavior of the compound. The isotropic and the anisotropic parts of the electron momentum density are calculated by means of the Compton profiles. The isotropic Compton profile is compared with our measurement deploying the 5Ci 241Am spectrometer based on the 59.54 keV gamma-rays and a good agreement is found. The anisotropies in the directional Compton profiles are also presented. The Mulliken population analysis is performed to see nature of bonding and occupied charges on the crystallographically distinct Cu and S atoms in CuS.