An abinitio study of the half-metallic properties of Co2TGe (T=Sc, Ti, V, Cr, Mn, Fe): LSDA+U method

Abstract

Using density functional theory (DFT) calculations, we investigated the electronic and magnetic properties of the Heusler compounds Co2TGe (T = Sc, Ti, V, Cr, Mn, Fe). Among the systems under investigation Co2CrGe and Co2MnGe have given 100% spin polarization at the Fermi energy (EF). Co2CrGe is the most stable half-metallic ferromagnets (HMFs) with an energy gap of 0.24 eV at the Fermi level (EF) in spin down channel. We have also found an increase in the total magnetic moments as T goes from Sc to Fe. The calculated magnetic moments for Co2CrGe and Co2MnGe are 3.999 µB and 5.00 µB respectively. Based on the local spin density approximation (LSDA) calculated results, we have predicted that the compounds Co2CrGe and Co2MnGe are HMFs. We have tried to study the HMFs in Co2ScGe, Co2TiGe, Co2VGe and Co2FeGe by using the local spin density approximation and Coulomb repulsion (U) (LSDA+U) when the simple generalized gradient approximation (GGA) or the LSDA fail.