It was noted that high-index surfaces of Si tended to facet into low-index planes. The only known exception, Si(113), had a surface energy about as low as that of Si(001). On the basis of scanning tunnelling microscopic measurements and ab initio theory, an atomic model of Si(113) was presented which employed the concept of a sub-surface self-interstitial. The calculated surface energy of Si(113)-(3 x 2) was close to the value for Si(001)-p(2 x 2). The new model explained experimentally observed transitions between the 3 x 1 and 3 x 2 phases.

Atomic Structure of Clean Si(113) Surfaces - Theory and Experiment. J.Da̧browski, H.J.Müssig, G.Wolff: Physical Review Letters, 1994, 73, 1660-3