Surface half-metallicity of CrAs in the zinc-blende structure

The development of new techniques such as the molecular beam epitaxy have enabled the growth of thin films of materials presenting novel properties. Recently it was made possible to grow a CrAs thin-film in the zinc blende structure. In this contribution, the full-potential screened KKR method is used to study the electronic and magnetic properties of bulk CrAs in this phase as well as the Cr and As terminated (001) surfaces. Bulk CrAs is found to be a half-metallic ferromagnet for all three GaAs, AlAs and InAs experimental lattice constants with a total spin magnetic moment of 3mu(B). The Cr-terminated surface retains the half-metallic character of the bulk, while in the case of the As-termination the surface states destroy the gap in the minority-spin band.