In the framework of Keating model, the effects of the symmetric and asymmetric two-body and three-body interactions between surface and substrate atoms on the formation of asymmetric dimers of Si(001)2×1 surface are discussed.The symmetric interactions induce the symmetric dimers.The results show that formation of asymmetric dimers of Si(00l)2×1 surface is mainly affected by the asymmetric three-body interactions rather than the two-body interactions.

The positions of atoms untill fifth layers of the reconstructed Si(100)2×1 surface are studied by simplex method. In addition, the reconstractions of diamond and Ge(100)2×1 are also investigated.