New π-Bonded Chain Model for Si(111)-(2×1) Surface

Several qualitatively different structural models have been examined in a critical evaluation of spectroscopic and other data for the Si(111)-(2×1) surface. Within the one-electron theory, only a novel π-bonded chain model with a covalent surface, and not the generally accepted buckled model with an ionic surface, is consistent with the data. © 1981 The American Physical Society.