Spin polarization and electronic properties of Co2MnSi/GaAs (001) heterojunction

Co2MnSi Heusler alloy, due to its half metallic properties and its potential applications in spintronic industry has attracted substantial attractions in recent years. Investigation of the interface properties of this alloy with well known semiconductors, such as GaAs, is of special interest. Hence, we studied the electronic and magnetic properties of Co2MnSi/GaAs (001) heterojunction by using spin density functional ab-initio method. The electron core interaction was approximated by pseudo potential method and the exchange correlation energy was calculated within Generalized Gradient Approximation (GGA). We limited our calculation to MnMn-As interface that was constructed by substituting Si with Mn atom. By examining the energy band and density of state curves we found out that a few interface states exist in the minority energy gap. However, the calculated spin polarization is 90%, much higher than the experimental 12% value. Furthermore, the band alignments were extracted for minority and majority spin channels.