Optical anisotropy of Cs nanostructures on III-V(110) surfaces

We present reflectance anisotropy spectra in the energy range 1.0-5.5 eV, measured for cleaved III-V surfaces after adsorption of caesium. In such a system Cs forms one-dimensional wire-like structures at low Cs coverages (Theta << 1 ML). The formation of these Cs wires leads to characteristic changes in the reflectance anisotropy spectra of the cleaved surface such as a minimum between the E-0 and E-1 bulk critical points of the substrate. For higher coverages the development of a two-dimensional layer can be optically monitored, as can the gradual transition to a three-dimensional disordered layer close to the saturation coverage.