First-principles calculations to investigate structural, electronic, magnetic, optical and thermodynamic properties of RE2Rh3Ge (RE = Pr, Sm)

Abstract

In this paper, we analyzed the physical characteristics of the ternary alloys RE2Rh3Ge (RE = Pr and Sm) using the first principles calculation based on functional density theory integrated in the Wien2k code. The calculated formation energies of Pr2Rh3Ge and Sm2Rh3Ge are −5.3827 and −5.2782 eV/atom, respectively, showing that these alloys may exist stably. The results of the band structure and density of states indicate that all of the compounds tested are magnetic metals, and their magnetism is mostly related to the contribution of Pr and Sm atoms. The total magnetic moments of Pr2Rh3Ge and Sm2Rh3Ge are 4.07245 and 11.16161 μB/f.u, respectively. Thermodynamic parameters such as heat capacity at constant pressure, entropy, Debye temperature, lattice volume, compressibility coefficients, and Grüneisen parameter alloys were calculated using the Gibbs algorithm and studied in depth over a large temperature range of 0–900 K. The Debye temperature increases with increasing pressure and decreases with decreasing temperature. Moreover, the Debye temperatures calculated at p = 0 GPa and T = 300 K are equal to be 342 and 322 K for Pr2Rh3Ge and Sm2Rh3Ge, respectively. The optical characteristics such as the real and imaginary portions of the dielectric function, the absorption coefficient, the energy-loss function, and the refractive index were investigated and discussed in more depth.