SURFACE REFLECTANCE ANISOTROPY OF C(100) AND SI(100) AB-INITIO CALCULATIONS WITHIN THE PSEUDOPOTENTIAL PLANE-WAVE APPROACH

The optical properties of C(100)2 x 1 and Si(100)2 x 1 surfaces are st udied by means of first-principle self-consistent DFT-LDA calculations within the pseudopotential plane wave approach. The self-consistent w ave functions and Kohn-Sham eigenvalues of the electronic structure ca lculations for the surfaces are used for the calculation of surface re flectance anisotropy. Qualitatively different spectra for the C(100) a nd the Si(100) surface are obtained. Whereas for the C(100) we find a strong anisotropy of the surface-state related optical peak, the refle ctance of the Si(100) surface appears nearly isotropic. The possible r easons for these different behaviours are discussed.