Reflectivity Anisotropy Spectra of Cu- and Ag- (110) surfaces from {\it ab initio} theory

We are able to disentagle the effects of the intraband and interband parts of the bulk dielectric function on the bare dielectric anisotropy of the surface. We show how the position, sign and amplitude of the structures observed in such spectra depend on the above quantities. The lineshape of all the calculated structures agree very well with the ones observed experimentally for samples treated by suitable surface cleaning. In particular, we reproduce the observed single peak structure of Ag at high energy, found to represent a state of the clean surface different from the one giving the originally observed double peak structure. This results is not reproduced by the 'local field' model.Comment: 4 pages, 3 figures. submitted to Phys. Rev. Let

Real-time study of dopant incorporation and segregation during MBE growth of GaAs(001):Si

The incorporation as well as segregation of dopant atoms during Si delta-doping of GaAs (001) has been studied in real-time by using reflection high-energy electron diffraction (RHEED) and reflectance anisotropy spectroscopy (RAS). Under conditions of enhanced Si adatom mobility distinct ordering processes are observed, which are promoted by ordered step arrays on the vicinal surface. The demonstrated real-time control of the complete delta-doping process is promising for a tailoring of doping structures

Study of clean and oxygen-covered Ag surfaces using opti­cal reflectance anisotropy

We report measurements of the azimuthal anisotropy in the normal incidence reflectance of clean and adsorbate-covered single crystal Ag(110) surfaces. Reflectance anisotropy spectra were taken between 1.5 and 5.5 eV photon energy. Previous studies in air had indicated a very large anisotropy in the region around the surface plasmon energy. On the clean surface this feature is strongly reduced compared to that observed on a contaminated surface. By oxygen dosage the (1×1) surface structure is modified to (4×1) and (2×1) as displayed by LEED. The simultaneously observed optical anisotropy shows a correlation with oxygen coverage and restores to a large extent the anisotropy observed in air

Local-field effects on the near-surface and near-interface screened electric field in noble metals

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