Electronic structure and interfacial geometry of epitaxial two-dimensional Er silicide on Si(111).

The two-dimensional band structure of a single epitaxial ErSi 2 layer on Si(111) is calculated by means of the crystalline extension of the extended Huckel method for various atomic structures and tested against experimental bands determined by angle-resolved photoemission. In particular, adopting for the silicide layer the structure proposed in previous work, i.e., a hexagonal Er monolayer underneath a buckled Si top layer, various possible interfacial geometries are investigated, namely with the Er in top, substitutional, T 4 , and H 3 sites of the Si(111) substrate and for the two possible orientations of the latter with respect to the buckled Si top layer