We investigate single domain $\beta$-SiC(100)-( $3\times 2$) surfaces (Si rich) by atom resolved scanning tunneling microscopy (filled and empty electronic states). Flat and high-quality surfaces having a low density of defects are grown with first identification of individual Si atoms and dimers. Si-Si dimers form rows perpendicular to the dimer direction in a ( $3\times 2$) atomic arrangement with clear evidence of asymmetric dimers all tilted in the same direction (i.e., not anticorrelated). Several types of defects are identified including primarily missing dimers and dimer pairs. Addition Si is grown epitaxially with two-dimensional island formation having the ( $3\times 2$) reconstruction.

• Received 22 May 1996

DOI:https://doi.org/10.1103/PhysRevLett.77.2013