Puckered (113) 3 x 1 and 3 x 2 models which were topologically similar to Ranke’s 3 x 1(2) model were deduced from the results of  ab initio  pseudopotential total-energy minimization calculations. Experimental observations of the coexistence of, and easy transition between, 3 x 1 and 3 x 2 reconstructions were supported by their small energy differences and their similar topology. It was noted that puckering produced a semiconducting electronic band structure with a gap around 1eV; in agreement with photo-electron spectroscopic data. An experimentally observed transformation of the 3 x 2 structure into a (3 x 1)-H structure, during H adsorption, was reproduced by relaxation calculations.

J.Wang, A.P.Horsfield, D.G.Pettifor, M.C.Payne: Physical Review B, 1996, 54[19], 13744-7