Soft X-ray studies of a c(4x2)(*) beta-SiC(100) surface

We report soft X-ray results for a Si-terminated beta-SiC(100) surface characterized by a c(4 x 2) plus a weak possibly (2 x 2) reconstruction in low-energy-electron diffraction. The existence of two surface Si 2p photoemission core levels is confirmed, shifted by -0.5 and -1.4 eV from the bulk-like level. We further show results which indicate that the component with the large -1.4 eV shift is correlated with the surface reconstruction. Surface-sensitive Si L(23) absorption spectra suggest the existence of a high density of unfilled s-like states about 1.3 eV above, as well as unfilled s-like states near, the bulk conduction band minimum. Reconstructed surfaces beyond this ''c(4 x 2)*'' surface are also noted.