Structural, elastic and thermodynamic properties of YRh: DFT study

Abstract

In the present study, we have performed ab-initio calculations for the equation of state parameters, elastic constants, and thermal properties of (B2-type) Yttrium-Rhodium (YRh) rare earth intermetallic compound. We have employed the projected augmented wave (PAW) pseudopotentials approach in the framework of the density functional theory (DFT) as implemented in the Quantum Espresso code, using both the local density approximation (LDA) and the generalized gradient approximation (GGA). The calculated lattice parameter of YRh compound agree very well with the available experimental one. The obtained results of the elastic constants are in general in good agreement compared to the theoretical ones reported previously in literature. The evaluated mechanical stability criteria indicate that YRh intermetallic compound is mechanically stable at equilibrium, while the anisotropy factor indicates that this material is characterized by a weak degree of anisotropy in its elastic properties. Calculations of Poisson’s ratio (ν) and Pugh’s ratio (B/G) both indicate that YRh intermetallic compound in B2 structure is ductile. Furthermore, several thermodynamic properties of YRh compound have been studied using Quasi-harmonic approximations (QHA). Our Calculations show that the vibrational free energy, the isothermal bulk modulus and the adiabatic bulk modulus decrease with increasing temperature, while all other calculated quantities increase with increasing temperature.