An STM study of the nature of the transitional phase of the GaAs(111) B surface

Abstract Scanning tunneling microscopy (STM) data are presented for all three phases of the GaAs(111)B surface prepared in situ by molecular beam epitaxy (MBE). The nature of the transitional phase is revealed for the first time by atomic resolution STM and shown to consist of structural units derived from both of the well known (2 × 2) and (√19 × √19)R23.4° surfaces. Individual ringlike units of the Ga-rich surface are stable structures on the (2 × 2) reconstructed surface. By varying the population of these features, the surface has access to a continuous stoichiometric pathway between the (2 × 2) and (√19 × √19)R23.4° reconstructions.