The linear optical response of reconstructed Sn/Si(111) surfaces

We have used the self-consistent tight-binding method in the extended Huckel approximation to calculate the electronic band structure and surface dielectric function of three Sn/Si(111) reconstructed surfaces. We show that the anisotropy in the imaginary part of the surface dielectric function and the corresponding reflection spectra as determined from the self-consistent wavefunctions for the three surfaces are quite different. This suggests that the recently developed technique of reflection anisotropy spectroscopy can be used in studying the change in surface reconstruction with increased Sn deposition.