title: Time-dependent tunneling spectroscopy for studying surface diffusion confined in nanostructures.
abstract: By confining a diffusion atom in a nanometer region using surface potential heterogeneity, we have successfully employed a time-dependent tunneling spectroscopy to quantitatively study its random motion. A hopping rate in the range of 1-10(4) Hz, approximately 3 orders of magnitude faster than those accessible by the existing diffusion methods based on scanning tunneling microscopy, was demonstrated for single Cu atoms diffusing in the faulted half unit cell of Si(111)-(7 x 7). Our technique is potentially useful to detect fast diffusion processes such as H quantum diffusion at atomic scale.
authors.affiliation: Department of Physics and Institute of Nano Science and Technology, Hong Kong University of Science & Technology, Hong Kong, China.
authors.forename: Kedong
authors.initials: K
authors.lastname: Wang
authors.forename: Chun
authors.initials: C
authors.lastname: Zhang
authors.forename: M M T
authors.initials: MM
authors.lastname: Loy
authors.forename: Xudong
authors.initials: X
authors.lastname: Xiao