Theoretical insight into the stability, magneto-electronic and thermodynamic properties of the new half-metallic ferromagnetic compounds Cr₂RbZ (Z=Ge, In and Sb): probed by DFT

The objective is to determine the structural, elastic, electronic, magnetic and thermodynamic properties of new half-metallic Cr₂RbGe, Cr₂RbIn and Cr₂RbSb by using the full-potential linearized augmented plane wave (FP-LAPW) method based on density functional theory and implemented in WIEN2K code. The exchange–correlation potential is evaluated using the generalized gradient approximation (GGA) within the Perdew-Burke-Ernzerhof (PBE) parameterization. Results on lattice parameters, bulk modulus, elastic, energy band gap and magnetic properties are reported. The elastic properties have shown the conformity of elastic constants with the stability criteria and the ductile nature of the compounds. The electronic band structures and density of states (DOS) of the compounds indicate they are half metallic because of the existence of the energy gap in the minority spin (DOS and band structure), which yields perfect spin polarization. These compounds Cr₂RbZ (Z = Ge, In and Sb) are found to be Half-metallic in the spin-down channel and metallic in the spin-up channel, which leads to a spin polarization of 100% with a integer magnetic moment of 8.00 μ_B, 8.00 μ_B and 9.00 μ_B for Cr₂RbGe, Cr₂RbIn and Cr₂RbSb respectively, is mainly contributed by the Cr atom. The thermodynamic stability of these compounds are also determined. In addition the temperature and pressure effects on the bulk modulus, heat capacities, Debye temperatures and entropy are computed and discussed in details, temperature and pressure dependence of thermodynamic properties of these materials have been examined in the ranges (0–1000 K) and (0–16 GPa), respectively. All the aforementioned results indicate that this new compounds would be an ideal candidate in spintronic.