Field-based scanning tunneling microscope manipulation of antimony dimers on Si(001)

The manipulation of antimony dimers, Sb-2, on the silicon (001) surface by means of a scanning tunneling microscope (STM) has been experimentally inve stigated. Directed hopping of the Sb2 dimers due the STM tip can dominate o ver the thermal motion at temperatures between 300 and 500 K. Statistics on the enhanced hopping are reported and possible tip-adsorbate models are di scussed focusing on a field-based interaction. The low yield of directed ho pping is believed to be due to the low gradient in the interaction energy i ntrinsic to a field-based mechanism. Ultimate resolution and limiting facto rs of this manipulation technique are discussed. (C) 2001 American Vacuum S ociety.