STM observation of the Si(111)-c(12x2)-Ag surface

The Si(111)-c(12x2)-Ag surface phase was observed by scanning tunneling microscopy (STM) at 65 K and its atomic structure was analyzed in detail. The phase is the ground-state structure within the framework of 'Honeycomb-Chain Channel' reconstruction, attained through successive phase transitions by cooling from 3x1 (>= ca. 500 K) and 6x1 phases (>= ca. 100 K). The transitions are likely order-disorder types with two-step freezing of fluctuation of the Ag atom positions.