BISMUTH ON GASB(110): ELECTRONIC AND DIELECTRIC PROPERTIES

We present a high-resolution electron-energy-loss-spectroscopy study of the electronic and dielectric properties of the (1 X 1) and (1 X 2) Bi/GaSb(110) interfaces, in the energy region of the semiconductor bulk gap. Among the semimetal/III-V(110) interfaces, we found this as the unique ordered-system showing a semimetallic character when one monolayer of semimetal is deposited on the (110) surface, at room temperature. Electronic loss structures induced by transitions among localized states have been identified for the (1 X 1) interface, the most prominent lying at about I eV. The (1 X 2) superstructure, produced through an appropriate thermal treatment, is still semimetallic, while the electronic loss structures shift to lower energies and present a clear dependence on the symmetry direction of the surface Brillouin zone.