Effects of Biaxial Strain on Stability and Half-metallicity of Cr and Mn Pnictides and Chalcogenides in the Zinc-blende Structure

The effects of biaxial strain, imposed by epitaxial growth conditions, on the half-metallicity properties of Cr and Mn pnictides and chalcogenides were investigated using local spin-density-functional calculations. The minority band gaps were found to decrease significantly under the biaxial strain, whereas the spin-flip gaps changed only slightly. The calculations show that under epitaxial conditions for any choice of substrate, CrSe, MnAs, MnSe, and MnTe cannot be half metallic; CrAs and CrTe are barely half metallic as their SF gap is close to zero; and only CrSb and MnSb remain distinct half metals with spin-flip gaps of 0.9 and 0.3 eV, respectively.