A theory for the cubic (001)-(3 x 2) surface, termed the 2-adlayer asymmetrical dimer model, was suggested on the basis of ab initio pseudopotential total-energy and grand canonical potential calculations. According to this model, two Si adlayers with a nominal total coverage of one monolayer were adsorbed at the clean Si-terminated surface. Asymmetrical dimers were formed in the top adlayer, with a dimer-bond length of 0.224nm. This model avoided the shortcomings of the single dimer-row, alternate dimer-row and double dimer-row models. It was the most stable structure among all of those considered. The calculated surface-band structure, as well as scanning tunnelling microscopic images, were in very good agreement with experimental observations.

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