First-principles total-energy calculations and scanning tunnelling microscopy were used to study the atomic structure of the clean or adsorbate-covered (113) surface. It was found that clean (113) 3 x 2 had a surface energy which was close to that of (001). The 3 x 2 cell contained a sub-surface interstitial; a novel entity which comprised an interstitial atom that was located below a quasi-molecular pentamer of surface atoms. The role of these interstitials was considered with regard to the formation of surface defects, with regard to temperature-induced or adsorbate-induced 3 x 2  3 x 1 phase transitions, with regard to mass transport on (113), and with regard to the transport of atoms across steps on (001).

J.Dabrowski, H.J.Müssig, G.Wolff: Solid State Phenomena, 1996, 47-48, 57-62