LOW-TEMPERATURE SCANNING-TUNNELING-MICROSCOPY ON VICINAL GE(100)

Using variable temperature scanning tunneling microscopy vicinal surfa ces of Ge(100) have been studied in a temperature range between 80 and 300 K (room temperature). Annealing the sample gives rise to a nonuni form terrace and step distribution. Terraces with dimer rows perpendic ular to the step edges cover approximately 3/4 of the entire surface. At room temperature about, of the surface is covered by buckled dimers . Dimers of straight SA steps are always pinned, i.e., they appear in their buckled form. On top of terraces buckling is also found, associa ted either with kinks in the step edges or in the formation of a singl e antisite dimer. At 80 K all dimers appear asymmetric in c(2x4) or p( 2x2) geometry. A transition between both structures may occur due to s ample-tip interaction which indicates that the energies of both recons tructions are rather similar. (C) 1996 American Vacuum Society.