Tip-Assisted Diffusion on Ag(110) in Scanning Tunneling Microscopy

Abstract

The influence of the tip in a scanning tunneling microscope on the atomic motion of Ag on Ag(110) is investigated at $T\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}50\mathrm{and}295\mathrm{K}$. At $T\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}50\mathrm{K}$ the tip can move single Ag atoms preferentially along [ $1\overline{1}0$] via an attractive interaction. At $T\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}295\mathrm{K}$, the tip can displace monatomic steps over distances as large as several hundred \AA{}. 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.