The effect of pressure on the structural, electronic, magnetic, and thermodynamic properties of the Mn2RuGe inverse Heusler alloy

Abstract In the frame of density functional theory, first-principles calculations based on generalized gradient approximation and quasi-harmonic Debye approximation model in which the phononic effects are taken into account have been carried out to investigate the structural, electronic, magnetic, and thermodynamic properties of full-Heusler alloy Mn 2 RuGe in CuHg 2 Ti-type structure in the pressure range of 0–50 GPa. Present calculations predict that Mn 2 RuGe is a ferrimagnet with an optimized lattice parameter of 5.854 A. The calculated total magnetic moment of 2.01  μ B per formula unit is very close to integer value and agree well with the Slater-Pauling rule, where the partial spin moments of Mn (A) and Mn (B) which mainly contribute to the total magnetic moment are 2.66  μ B and −0.90  μ B , respectively. In the study of the energy band structures and density of states, Mn 2 RuGe exhibits half-metallicity with an indirect gap of 0.235 eV in the spin-down channels, and the shifting of bands towards higher energies in spin-down channel under high pressure. Meanwhile, the high-pressure thermodynamic properties of Mn 2 RuGe, such as the pressure-volume-temperature relationship, bulk modulus, thermal expansivity, heat capacity, Debye temperature, and Gruneisen parameter are evaluated systematically in the temperature range of 0–900 K. This set of data is considered as the useful information to understand the high-pressure and high-temperature properties for the Mn 2 RuZ-type Heusler alloy family.