Puckered Si(113) 3×1 and 3×2 models topologically similar to Ranke’s 3×1(2) model are found from ab initio pseudopotential total-energy-minimization calculations. The experimental observations of coexistence of and ready transition between 3×1 and 3×2 reconstructions are supported by their small energy differences and similar topology. Puckering produces semiconducting electronic band structure with a gap around 1 eV in agreement with photoelectron spectroscopy. The transformation of the 3×2 structure into a 3×1-H structure upon H adsorption observed experimentally is confirmed by relaxation calculations. Scanning tunneling microscopy images are discussed. © 1996 The American Physical Society.

• Received 22 July 1996

DOI:https://doi.org/10.1103/PhysRevB.54.13744