Electron correlation effects on SiC(111) and SiC(0001) surfaces
Abstract
The possibility is discussed that, independent of the polytype, large electronic correlation effects give rise to semiconducting SiC surfaces with [111] or [0001] orientations. The most important surface translational symmetries (\sqrt {3}\times \sqrt {3}){\mathrm
{R}}30^\circ and 3 × 3 are considered. The discussion is based on the detailed knowledge of the surface atomic geometries and the electronic structures derived for these geometries using a local density approximation for exchange and correlation. It is argued that the resulting halffilled, weakly dispersive danglingbond bands within the fundamental gaps are split according to a Hubbard interaction parameter U, and that the surface systems undergo a MottHubbard transition. Such a physical picture provides a qualitatively correct account of the singleparticle excitation spectra either inferred from angleresolved photoemission and inverse photoemission experiments or obtained from scanning tunnelling spectroscopy. The gap opening and hence the Hubbard U parameter are discussed in terms of their dependence on the surface reconstruction as well as the SiC polytype.
 Publication:

Journal of Physics Condensed Matter
 Pub Date:
 May 2004
 DOI:
 10.1088/09538984/16/17/014
 Bibcode:
 2004JPCM...16S1721B