First-principles exploration of the pressure dependent physical properties of Sn4Au: a superconducting topological semimetal

Abstract

First-principles investigation within the density functional theory is utilized to explore the physical properties of a superconducting topological semimetal Sn4Au under pressure within the range of 0-5 GPa. According to the computed elastic moduli, the compound under study is classified as ductile and applied pressure enhances the ductility. The compound has very high level of dry lubricity and machinability index. All the anisotropy factors demonstrate an elastically anisotropic nature. The electronic properties are investigated in view of the electronic band structure and density of states. The band structure reveals the topological semimetallic feature of Sn4Au while the density of states at the Fermi level decreases gradually with increasing pressure. Both ionic and covalent bondings are observed in Sn4Au. Optical parameters of Sn4Au are investigated at different pressures. The characteristic peaks in reflectivity, refractive index and photoconductivity exhibit a shift towards higher energy with increasing pressure for all polarizations of the electric field vector. The absorption coefficient and reflectivity spectra designate Sn4Au as a suitable system for optoelectronic applications. Moreover, the pressure dependent shifts in the electronic density of states at the Fermi level, the changes in the Debye temperature, and pressure induced variations in the repulsive Coulomb pseudopotential have been used to explore the effect of pressure on the superconducting transition temperature in this study.