Half-metallic properties and the robustness of Co2MnGe Heusler alloy under pressure: Ab-initio calculation

Abstract

To investigate the structural, mechanical, electronic and magnetic properties of full Heusler Co2MnGe in L21 structure, we used first-principle calculations. We made use of all-electron full potential linearized muffin-tin orbital method (FP-LMTO) within the density functional theory. The generalized gradient approximation GGA allows describing the exchange correlation energy. The obtained lattice parameters, bulk modulus and its derivate are in good agreement with experimental and theoretical values. We have also calculated the elastic constants and their related parameters. GGA + U approach allows to process electronic properties. For our compound, the band structure and magnetic moments are treated at equilibrium lattice constant. At Fermi level, the material has a semi metallic behavior with 100% spin polarization ratio. Computed magnetic exchange constants are used to evaluate the Curie temperature from mean field-approximation (MFA). Finally the elastic constants, electronic structure and magnetic properties are investigated at high-pressure. We noticed that half-metal to metal transition was around 102 GPa. The increasing pressure does not affect-the total magnetic moment and the overall shape of the band structure which indicates the robustness of electronic structure of this system.