AN STM STUDY OF THE NATURE OF THE TRANSITIONAL PHASE OF THE GAAS(111)B SURFACE

Scanning tunneling microscopy (STM) data are presented for all three p hases of the GaAs(111)B surface prepared in situ by molecular beam epi taxy (MBE). The nature of the transitional phase is revealed for the f irst time by atomic resolution STM and shown to consist of structural units derived from both of the well known (2 x 2) and (root 19 x root 19)R23.4 degrees surfaces. Individual ring-like units of the Ga-rich s urface are stable structures on the (2 x 2) reconstructed surface. By varying the population of these features, the surface has access to a continuous stoichiometric pathway between the (2 x 2) and (root 19 x r oot 19)R23.4 degrees reconstructions. (C) 1997 Elsevier Science B.V. A ll rights reserved.