SUPERPERIODICITY IN THE THERMAL FACETING OF AU(111) VICINAL SURFACES

Using scanning tunneling microscopy and low energy electron diffractio n, the thermal faceting of two Au(111) vicinal surfaces belonging to t he [011] zone is investigated. Above 700 K, a final stable state is fo und: it consists of a periodic succession of (111) and (755) facets. T he superperiod is 70 Angstrom for Au(1199) and 110 Angstrom for Au(433 ). The quantitative agreement between our results and the observations of macroscopic gold crystals strongly suggests that the novel periodi c morphology is an equilibrium state. Possible origins to account for this morphology are discussed.