Insight into elastic anisotropy, mechanical and dynamical stability, electronic properties, bonding and weak interactions analysis of LuAuSn Half-Heusler

Abstract

Despite their great interest showing that LuAuSn half-Heusler is a topologically trivial semimetal, most of information about its physical behaviors seem rather remote from completion for the fact that several of its physical properties remain still unknown. Therefore, we try to outline, going into much specific details, a study on elastic anisotropy, mechanical and dynamical stability, electronic properties as well as the analysis of bonding and weak interactions. The lattice parameter value obtained by GGA-WC is very close to the experimental one, therefore, this functional has been chosen to carry out the rest of this work. The detailed study of the elastic behavior has revealed the mechanical stability of this compound, it results that its structure resists to slight strains. The obtained results also indicate a large elastic anisotropy of LuAuSn. Electronic results obtained by TB-mBJ(SOC) have confirmed its semimetallic behavior as well as being topologically trivial. This last property has been confirmed not only by the absence of band overlap but also by the absence of band inversion by the analysis of fat bands with and without SOC effect. The analysis of bonding and weak interactions has shown that the covalent character is predominant with the presence of weak repulsive interactions in cage regions and strong repulsive interactions between Lu and Sn. The vibrational study has revealed the dynamical stability of LuAuSn in the ground state, which indicates that this compound keeps its half-Heusler structure even at very low temperatures. Also, its zone center phonon modes have been determined and analyzed in detail by showing their frequencies and polarizations.