AVS 47th International Symposium
    Surface Science Thursday Sessions
       Session SS3-ThM

Paper SS3-ThM10
Dynamics of the Flip-Flop Motion of Single Buckled Dimers of Si(100)

Thursday, October 5, 2000, 11:20 am, Room 210

Session: Surface and Interface Structure II
Presenter: H. Kenji, University of Tsukuba, Japan
Authors: H. Kenji, University of Tsukuba, Japan
M. Ryuji, University of Hokkaido, Japan
Y. Mikio, University of Hokkaido, Japan
H. Shigekawa, University of Tsukuba, Japan
Correspondent: Click to Email
We report the direct observation of the flip-flop motion of single buckled dimers of Si(100) in real space by hovering the tunneling tip of scanning tunneling microscope over a pre-selected atom of the flip-flopping dimers and measuring the tunneling current. By this method, the complete time trace of the flip-flop motion of single dimers can be obtained, and from it, any desired properties of the dynamics can be deduced. Each dynamical flip-flop event (up to 200,000) was clearly resolved, and the time trace of the tunneling current shows that the flip-flop motion is a switching between two stable configurations. A statistical analysis of the autocorrelation function elucidates that the flop-flop motion is a stochastic process described by a two level system. The influence of the local environment on the dynamics of the flop-flop motion can be mapped out by executing the measurements on neighboring dimers. We found that the details of the dynamics of the flip-flop motion differ from dimer to dimer and from domain to domain. The activation energy of the flip-flop motion differs significantly (measured 32 meV, estimated 110~ meV) for dimers in different domains. http://dora.ims.tsukuba.ac.jp