Surface electronic structure of metastable FeSi(CsCl)(111) epitaxially grown on Si(111)

We report an investigation on the electronic structure of metastable, epitaxial FeSi films grown on Si(111). The electronic structure of the metastable silicides was probed with angle-resolved photoemission, and com-pared with theoretical calculations. We identify the silicide as FeSi crystallizing in the CsCl structure. Its surface is Fe terminated, and presents a prominent, strongly dispersing surface state at a binding energy of -3.5 eV in <(Gamma)over bar>. Its origin lies in the truncation of Fe bonds at the surface, and thus it has a major Fe d(z)2 content.