Structural property and half‐metallicity for 3d transition metals on GaAs surface

The structural and magnetic properties of the surface and interface are studied for the hypothetical zinc‐blende phase of 1–2 monolayers (MLs) M (= Cr, Mn, Fe, or Co) on GaAs(001) or AsGa(001) by first‐principles calculations. We present the energetics for the systems of mixed M (Ga,As) and of a M overlayer on the substrate in order to obtain a systematic understanding of interfacial mixing. A heterointerfacial mixing of M (Ga,As) on GaAs(001) or AsGa(001), which consists of a tetrahedrally coordinated M atom of an empty site, is energetically favorable. The mixed M (Ga,As) (hypothetical zinc‐blende) with 1–2 ML M on GaAs(001) is more energetically stable than the zinc‐blende M (Ga,As). A surface Cr atom on an As‐terminated substrate retains the half‐metallicity in the case of 1–2 ML M with a zinc‐blende lattice, while it disappears for the surface Cr atom of the Ga termination. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)