Investigation of Heusler alloy-semiconductor interfaces

Abstract

Using the electron density functional theory, the electronic structure and magnetic properties of possible contacts on the (001) interface between XYZ and X 2 YZ Heusler alloys (NiMnSb, Co2 MnSi) and III–V semiconductors (InP, GaAs) are studied. It is demonstrated that, in both cases, the high degree of spin polarization is achieved in Ni/P(As) or Co/As contacts. The influence of structure defects located on the surface and interfaces on the spin polarization at the Fermi level is studied. The nature of surface states at the Heusler alloy-semiconductor interface and electron factors that favor preservation or loss of the half-metallic behavior in the contacts are analyzed. Calculations of the local magnetic moments show that the magnetic properties of atoms in the contact are not changed significantly at the interface because of the partial compensation of their coordination by atoms of the semiconductor. The spin polarization can be increased by doping of the X element sublattice.