Investigation of mechanical, thermodynamical, dynamical and electronic properties of RuYAs (Y = Cr and Fe) alloys

Investigation of structural, dynamical, mechanical, electronic and thermodynamic properties of RuYAs (Y = Cr and Fe) alloys have been performed from the first principle calculations. Among the three structural phases, 'alpha' phase is found to be energetically favorable for both the RuCrAs and RuFeAs compounds. The computed cohesive energies and phonon dispersion spectra indicate the structural and dynamical stabilities of both the compounds. Mechanical stability of these compounds are studied using elastic constants. The Pugh's ratio predicts RuFeAs to be more ductile than RuCrAs. The RuCrAs alloy, on the other hand, is found to be a stiffer, harder and highly rigid crystal with stronger bonding forces than the RuFeAs. Furthermore, the thermodynamical properties have also been estimated with respect to the temperature under different pressures using the quasi-harmonic Debye model. In order to account for the effect of the highly correlated d transition elements in the system we incorporated the GGA + U approximations. Within the GGA + U approach, the electronic structure reveals the half-metallicity for both compounds, which follows the Slater-Pauling rule. The charge density and electron localized function reflect the covalent bonding among the constituent atoms. Bader analysis reveals that the charge transfer takes place from Cr/Fe to Ru and As atoms in both approximations. Both Raman and infrared active modes have been identified in the compounds.

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In this study, the structural, dynamical, mechanical, electronic, and thermodynamic properties of RuYAs (Y = Cr and Fe) alloys were investigated using first-principles calculations. The energetically favorable structural phase was found to be the 'alpha' phase for both RuCrAs and RuFeAs compounds. The computed cohesive energies and phonon dispersion spectra indicated the stability of both compounds. Mechanical stability was studied using elastic constants, which revealed that RuFeAs is more ductile than RuCrAs. The thermodynamic properties were estimated using the quasi-harmonic Debye model under different pressures. The electronic structure, analyzed using the GGA + U approach, showed half-metallicity for both compounds and covalent bonding among the atoms. Bader analysis revealed charge transfer from Cr/Fe to Ru and As atoms. Raman and infrared active modes were identified in the compounds.