Spin-wave dispersion of Co₂Mn_1-<i>x</i>Fe<i>_x</i>Si based on the quasi-particle self-consistent <i>GW</i> calculation

Co-based full Heusler alloys with half-metallicity are capable of spin-current resources or materials for giant magnetoresistance (GMR). It is important to reveal the electronic structures of these materials and the magnetic properties. In this study, we calculate the electronic structure and spin-wave dispersion of Co₂Mn_1-xFe_xSi (x=0.00, 0.25, 0.50, 0.75, 1.00) within the quasi-particle self-consistent GW (QSGW) method. In ecalj package, we implemented the QSGW calculation for electronic structures. The dynamical transverse spin susceptibility are calculated based on the linear response theory. The spin-wave dispersions are described as the imaginary part of the susceptibility. The calculated density of states at Fermi energy decrease as the Fe concentration increases. It differs the electronic structures experimentally predicted from the Gilbert damping constant. The calculated stiffness constant decreases from 294 meV Ų (Co₂MnSi) to 59 meV Ų (Co₂FeSi). It is same tendency as the experimental stiffness constant by the temperature dependence of magnetization.