A comparative study of a Heusler alloy Co2FeGe using LSDA and LSDA plus U

We have calculated the on-site Coulomb repulsion (U) for the transition elements Co and Fe. To study the impact of Hubbard potential or on-site Coulomb repulsion (U) on structural and electronic properties the calculated values of U were added on GGA and LSDA. We performed the structure optimization of Co2FeGe based on the generalized gradient approximation (GGA and GGA+U). The calculation of electronic structure was based on the full potential linear augmented plane wave (FP-LAPW) method and local spin density approximation (LSDA) as well as exchange correlation LSDA+U. The Heusler alloy Co2FeGe fails to give the half-metallic ferromagnetism (HMF) when treated with LSDA. The LSDA+U gives a good result to prove that Co2FeGe is a HMF with a large gap of 1.10 eV and the Fermi energy (E-F) lies at the middle of the gap of minority spin. The calculated density of states (DOS) and band structure show that Co2FeGe is a HMF when treated with LSDA+U. (C) 2012 Elsevier B.V. All rights reserved.