Structure of the GaAs((1)over-bar(1)over-bar(2)over-bar)B surface

The GaAs((1) over bar(1) over bar(2) over bar )B surface was prepared by molecular beam epitaxy and investigated by in situ scanning tunneling microscopy with respect to structure and morphology. A remarkable surface corrugation with (0 (1) over bar(1) over bar) and ((1) over bar0 (1) over bar) facets was observed at Ga-rich condition. The period of the corrugation is about 12nm. The Ga-rich structure changed into an As-rich structure, when the sample temperature was decreased to below about 520degreesC under As-2 flux. The As-rich surface is also not flat but undulated on a sub-gm scale. On an atomic scale it is rather rough being composed of fragments of ID chains along [1 (1) over bar0]. There is a twofold periodicity along [1 (1) over bar0], but little periodicity along [11 (1) over bar]. (C) 2004 Elsevier B.V. All rights reserved.