Exploring the structural, electronic, mechanical and optical behavior of two phases of topological superconductor candidate Au2Pb by first-principles calculations

Abstract

A vital initial step towards comprehending quantum materials with topologically non-trivial order parameters is to study superconductivity in Dirac materials. In this work, we thoroughly analyzed the elastic, electronic, and optical characteristics of two phases (cubic Laves phase and orthorhombic phase) of topological superconductor candidate Au₂Pb by using density functional theory. High-temperature cubic Au₂Pb has an electronic band structure with a Dirac cone that gaps as it transforms structurally into a low-temperature superconducting orthorhombic phase. Au₂Pb is a mechanically stable, ductile, highly machinable, and very soft material according to the analyses of calculated elastic properties. An extremely low Debye temperature value indicates that Au₂Pb is a very soft substance and supports the idea that its bonding strengths are weak. The material also shows anisotropic optical characteristics in the orthorhombic phase. Au₂Pb has extremely dispersive bands that extend above the Fermi level, which exhibits its metallic characteristics. Au₂Pb has high, nonselective reflectivity over a broad spectral spectrum. The substance has enormous potential to be used as a powerful UV reflector. Applications based on optoelectronic devices can make use of all these optical properties.