Electronic structure calculations of thin films of RbF

Abstract

Electronic structure of thin films of rubidium fluoride is investigated within a next-nearest-neighbour approximation of the LCAO approach, with overlap integrals included. For the bulk structure calculations, semi-empirical parameters are fitted in order to reproduce the experimental band gap width, electron affinity and ionicity of RbF. For the thin-film structure calculations, one center parameters are corrected to take into account the Madelung potential differences in the subsequent atomic layers of a considered slab. For very thin films (two lattice constants or less), a strong dependence of the valence band width as well as the layer-density-of-states distributions on the slab thickness is found. The surface electronic structure of RbF is examined and it is shown—in accordance with previous estimations—that no surface states exist at the (001) surface.