Low-temperature manipulation of Ag atoms and clusters on a Ag(110) surface

We report on manipulation experiments performed with a scanning tunneling microscope (STM) on Ag(110) at T = 50 K. At high tunneling currents (I = 50 nA) the tip can move individual atoms and small clusters preferentially through troughs between densely packed atomic rows. At lower tunneling currents cross-channel motion along the diagonal of the surface unit cell occurs which may indicate adatom-surface atom exchange processes during the tip-induced motion. The interaction between the tip and the Ag adatom is shown to be attractive or repulsive depending on the polarity of the bias voltage. The transfer of Ag adatoms to the tip and the subsequent redeposition are characterized in terms of current versus distance measurements.