Spin injection and filtering in halfmetal/semiconductor (CrAs/GaAs) heterostructures"

Theoretical investigations of spin-dependent transport in GaAS/CrAs/GaAs halfmetal-semiconductor heterostructures indicate that this system is a candidate for an efficient room temperature spin injector and filter. The spin dependent electronic structure of zincblende CrAs and the band offset between GaAs and CrAs are determined by ab-initio calculations within the method of linear muffin tin orbitals (LMTO). This band structure is mapped onto an effective sp3d5s* nearest neighbor tight-binding (TB) Hamiltonian and the steady-state transport characteristic is calculated within a non-equilibrium Green’s function approach. Even at room temperature we find current spin polarizations up to 97%.