The computational design of zinc-blende half-metals and their nanostructures

Abstract

The influence of atomic disorder and heterointerfaces with III–V semiconductors on theelectronic and magnetic properties of zinc-blende (ZB) CrAs is studied by ab initiocalculations based on density-functional theory. Antisite Cr spins are coupledantiferromagnetically with the Cr spins at the ordinary sites, while the ferromagneticcoupling between the Cr spins at the ordinary sites is robust against defect formation. Thedegree of spin polarization is not reduced significantly by the impurity bands formed in theminority spin energy gap. In the ZB CrAs/GaAs junction, relatively high spin polarizationis retained even at the interface in contrast to usual half-metal/semiconductorheterojunctions. Complete spin polarization is also preserved throughout ZB CrAs/GaAsmultilayers and it is insensitive to the substitutional disorder between Cr and Ga sites.