OBSERVATION OF STEP CONFIGURATION CONVERSION ON SINGLE-DOMAIN SI(001)1X2 SURFACE BY SCANNING TUNNELING MICROSCOPE

We have observed a conversion of step configuration of 3.5 degrees mis cut Si(001) surface after depositing several monolayers of Ge by using a scanning tunneling microscope. For a 3.5 degrees miscut Si(001) sur face, terraces are spaced by double-atom height steps and all dimer ro ws, either on the upper terrace or on the lower terrace of a step, are normal to the step edge, defined as single-domain (1 x 2) surface. Af ter depositing 2 ML of Ge, the surface is still single domain, but dim er rows have changed their direction, running parallel to the step edg e and single domain (2 x 1) appeared. The reason for such conversion i s attributed to the strain that existed on the epilayer of Ge. (C) 199 6 American Institute of Physics.