Ab-initio insights into the elastic, bonding, phonon, optoelectronic and thermophysical properties of SnTaS2

SnTaS2 is a recently discovered layered semimetal exhibiting type-II low transition temperature superconductivity. Except some superconductivity related parameters, most of the physical properties, namely, elastic, mechanical, bonding, phonon dispersion, acoustic, thermophysical, and optical properties of SnTaS2 are unexplored till now. In this study, we have investigated these hitherto unexplored properties of SnTaS2 for the first time employing density functional theory (DFT) based first-principles method. SnTaS2 is a mechanically stable, elastically anisotropic compound with strongly layered feature. The bond hardness and Vickers hardness have been calculated. The material under study is ductile, soft and highly machinable. The chemical bonding feature has mixed character with significant contribution coming from the ionic channel. Phonon dispersion curves disclose dynamical stability. Electronic band structure calculations show simple metallic character. The Fermi surface consists of both electron-like and hole-like sheets with varying degrees of dispersion. The low energy (including visible part of the spectrum) refractive index of SnTaS2 is high. The reflectivity is fairly nonselective over a wide range of photon energy and the absorption coefficient is large in the mid ultraviolet region. The Debye temperature and thermal conductivity of SnTaS2 are low. The electron-phonon coupling constant has been calculated. The compound under study possesses optical anisotropy with respect to the polarization direction of the incident electric field.