ELECTRONIC-STRUCTURE AND MAGNETIC-ORDERING ON THE (001) SURFACES OF FEAL, COAL AND NIAL ALLOYS WITH BULK B2-STRUCTURE

The electronic structure of (001) surfaces of the B2-structure alloys, FeAl, CoAl and NiAl, has been calculated using the scalar-relativisti c, spin-polarized FLAPW method. Symmetrical 7-layers films with the su rface layer formed by atoms of a transition metal were considered. The data on the distribution of electronic charge and spin over the unit cell, local densities of states, total and partial layer-by-layer char ges and magnetic moments have been obtained. The values of the work fu nction for the (001) surfaces of FeAl, CoAl and NiAl are 4.79, 4.90 an d 5.17 eV, respectively. The NiA1 (001) surface is found to be magneti cally dead, while the FeAl (001) and CoAl (001) surfaces exhibit ferro magnetic ordering (the values of the surface magnetic moments are 2.75 7 and 1.12 mu(B) respectively). The magnetic moments of inner layers s harply decrease towards the bulk-like layers.