  The structure of thin terminated Bi(1 1 1) films of approximately 1 nm
thickness is investigated from first principles. Our density functional theory
calculations show that covalent bonds to the surface can change the orientation
of the films completely. For thicker films, the effect is limited to the
surface only. Based on these observations, we further present a simple model
structure for the native oxide and chemically similar oxides, which form a
protective capping layer, leaving the orientation of the films unchanged. The
advantages of this energetically favorable layered termination are discussed in
the context of the films' technological exploitation in nanoelectronic devices.
