Tip-assisted diffusion on Ag(110) in scanning tunneling microscopy

The influence of the tip in a scanning tunneling microscope on the atomic motion of Ag on Ag(110) is investigated at T = 50 and 295 K. At T = 50 K the tip can move single Ag atoms preferentially along [1(1) over bar0$] via an attractive interaction. At T = 295 K, the tip can displace monatomic steps over distances as large as several hundred Angstrom. The structures thus created decay on a time scale of minutes. In contrast to prevailing assumptions significant tip-induced disturbances of the equilibrium shape of steps are observed even at sub-nA tunneling currents.