AB-INITIO LMTO CALCULATION OF SURFACE LOCALIZED AND RESONANCE STATES OF THE SIC(110) ZINCBLENDE SURFACE

The surface localized and resonance states of unrelaxed and relaxed Si C(110) zinc-blende surfaces have been investigated within the local de nsity approximation of density functional theory (DFT), employing a fi rst-principles full-potential self-consistent linear muffin-tin orbita l (LMTO) method using a thicker (thirteen layer) slab. Intrinsic surfa ce states appear in the fundamental energy gap for the unrelaxed surfa ce. We have allowed non-bond-length-conserving relaxation of the surfa ce atoms to obtain the minimum energy configuration. The shift in the surface states arising from the relaxation of atoms is small in compar ison to other studied heteropolar covalent semiconductors because of t he smaller value of the relaxation angle of the SiC(110) surface. New surface states have been predicted in the valence band region. The pre sent atomic geometry is somewhat different from other theoretical resu lts. We observe an inward displacement of the Si cation and an outward displacement of the C anion both parallel and perpendicular to the su rface, different from the results of Sabisch et al. No experimental da ta are available for comparison.