Exploring of the structural stability, mechanical, electronic and optical properties of hydrogenated RE5Si4 (RE=Sc and Y) from first-principles calculations

Abstract

In order to expand the applications of rare-earth ultrahigh-temperature materials, the overall performances including the hydrogenated mechanism, mechanical and optical properties of hydrogenated RE5Si4 (RE = Sc and Y) were explored and discussed by the first-principles calculations. It provides the theoretical support for the development and application of RE5Si4 silicides. Three hydrogenated models were considered based on the structural properties of RE5Si4 silicides. The results illustrate that the hydrogenated RE5Si4 are thermodynamically stable for the reason of the electronic interaction between hydrogen and RE5Si4 (RE = Sc and Y). Moreover, the elastic modulus and elastic constants demonstrate that the hydrogenated RE5Si4 display the worse mechanical properties than parent RE5Si4. Additionally, the doped H (2) models for Y5Si4 display the ductile behavior. The electronic structures show that all hydrogenated models possess metallic properties. And the stability of hydrogenated models and the localized hybridization between RE5Si4 and hydrogen atoms are closely related. Finally, the adsorption spectrum confirms that the hydrogen atomic doping improves the electronic jump between the occupied states and the empty states.