A first-principles study on surface and interface magnetism of Fe/B2-FeSi(001)

We investigated the surface and interface magnetism of Fe/B2-FeSi(001) by using the full-potential linearized augmented plane wave method within the generalized gradient approximation to density functional theory. We considered two Fe monolayers covering FeSi(001) with the Fe interfaced [2Fe/FeSi(001) = 3Fe/SiFe(001)] and Si interfaced [2Fe/SiFe(001)] systems as well as the Fe terminated [FeSi(001) = 1Fe/SiFe(001)] and Si terminated [SiFe(001)] systems. We found that the interlayer distances between the Fe and Si are expanded, in the sense of average, from the unrelaxed one, based on the total energy and atomic force calculations, while those between the Fe layers are contracted. It is calculated that SiFe(001) is nonmagnetic. The calculated magnetic moments of surface Fe layers are 3.02, 2.95, and 2.38 mu(B) for the 3Fe/SiFe(001), 2Fe/SiFe(001), and 1Fe/SiFe(001) systems, respectively. In all the systems, we found that the local magnetic moments of the inner layers are abruptly suppressed to almost zero, but finite, inside the first Si layer from the surfaces. (C) 2003 Elsevier B.V. All rights reserved.