A model for the (001)-(3 x 2) surface of the cubic phase, the so-called 2-adlayer asymmetrical dimer model, was suggested on the basis of ab initio pseudopotential total energy and grand canonical potential calculations. In this model, two Si adlayers with a nominal total coverage of 1 monolayer were adsorbed onto the clean Si-terminated surface. Asymmetrical dimers were formed in the top adlayer, with a dimer-bond length of 0.224nm. This model overcame the problems of previous models; such as the single-dimer row, alternate-dimer row, and double-dimer row, and it was the most stable structure among all of the configurations which were considered. The calculated surface-band structure, as well as the filled- and empty-state scanning tunnelling microscope images for this reconstruction, were in very good agreement with experimental observations.

Atomic and Electronic Structure of β-SiC(001)-(3 x 2) W.Lu, P.Krüger, J.Pollmann: Physical Review B, 1999, 60[4], 2495-504