Many-body correlation effects on the (110) and (111) silicon inversion layers

Self-consistent local-density-functional and Green's-function perturbational techniques are employed in parallel to investigate many-body exchange-correlation effects on the electronic structure of space-charge layers in Si-SiO₂ (110) and (111) systems. Quantitatively, the self-energy corrections depend only on the temperature and electron density and are insensitive (within 3-4%) to the surface orientations and to the surface valley degeneracies in the 0-300-K temperature and 10¹¹-3×{}10¹²-cm^-2 electron-density ranges. Results show important many-body effects even at room temperature. Connection with the available experimental data (in particular, on the puzzling valley-degeneracy question) on the subband structure is made.