An ab initio approach to understand the structural, thermophysical, electronic, and optical properties of binary silicide SrSi2: A double Weyl semimetal

TL;DR

This study employs density functional theory to comprehensively analyze the structural, thermophysical, electronic, and optical properties of the double Weyl semimetal SrSi2, revealing its stability, semimetallic nature, and potential optoelectronic applications.

Contribution

It provides the first detailed ab initio investigation of SrSi2's elastic, thermophysical, electronic, and optical properties, highlighting its stability and application potential.

Findings

SrSi2 is mechanically stable, ductile, and relatively soft.

It exhibits semimetallic character with Weyl nodes near the Fermi level.

Optical analysis shows high reflectivity and ultraviolet absorption, suitable for optoelectronic devices.

Abstract

A large number of hitherto unexplored elastic, thermophysical, acoustic, and optoelectronic properties of a double Weyl semimetal SrSi2 have been investigated in this study. Density functional theory (DFT) based methodology has been employed. Analyses of computed elastic parameters reveal that SrSi2 is a mechanically stable, ductile, moderately machinable, and relatively soft material. The compound is predicted to be dynamically stable and possesses significant metallic bonding. Study of thermophysical properties, namely, Debye temperature, Gr\"uneisen parameter, acoustic parameters, melting temperature, heat capacity, thermal expansion coefficient, and dominant phonon mode is also indicative of soft nature of SrSi2. The electronic band structure calculations without and with spin-orbit coupling disclose semimetallic character with clear Weyl nodes close to the Fermi level. The electronic dispersion is anisotropic characterized by nearly flat and linear regions within the Brillouin zone. Optical parameters at different photon energies are investigated. SrSi2 shows excellent nonselective reflection spectrum across an extended range of energy encompassing the visible region implying that the compound under study has significant potential to be used as an efficient solar energy reflector. SrSi2 absorbs ultraviolet light quite efficiently. The compound also possesses high refractive index in the low energy. All these optical features can be useful in optoelectronic device applications.