A first-principles study of electronic structures and magnetism for a Mn2As(001) surface

The electronic structures and magnetic properties of Mn-terminated Mn2As (001) surfaces were investigated by using the full-potential linearized augmented plane wave method within the generalized gradient approximation. We considered three different types of Mn-terminated Mn2As(001) surfaces, i.e., Mn(I)term, Mn(II)1-term, and Mn(II)2-term. The calculated results showed that the magnetic moment of the surface Mn(II) atom in the Mn(II)1-term was greatly increased to 4.46 mu(B) which was close to that of the free Mn atom. Those of the surface Mn(I) atom in the Mn(I)-term and the surface Mn(II) atom in the Mn(II)2-term were also considerably enhanced to 3.38 and 3.77 mu(B) compared with the center (1.97 mu(B)) and deep inner (3.23 mu(B)) layers, respectively. These results were discussed in relation with the band narrowing at the surfaces and the hybridization between the Mn-d and As-p states using the calculated spin polarized layer projected density of states. (c) 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.