Missing dimer defect on b-SiC(0 0 1)-c(2 2) surface—numerical analysis of the structure and STM profiles

The carbon-terminated b-SiC(0 0 1) surface is known to be reconstructed with carbon triple-bond dimers at silicon bridge sites. STM investigations of this surface suggest asymmetric dimers tilted in the same direction and defects in form of missing dimer bordered on strongly tilted dimers and dimer rows. In order to verify this interpretation of experimental results we have performed LDA-MD calculations of the geometry and electronic structure of ideal and defected SiC(0 0 1)- c(2 2) surface, followed by a theoretical analysis of the formation of STM images for this system. Our results indicate existence of a structure of tilted dimers surrounding missing dimer defect in contrast to flat bridging dimers at undefected surface.