STM images apparently corresponding to a stable structure:: Considerable fluctuation of a phase boundary of the Si(111)-(√3 x √3)-Ag surface -: art. no. 156102

We study scanning tunneling microscopy (STM) images near a phase boundary of the Si(111)-(root3 x root3-)-Ag surface by using Monte Carlo simulations based on results of first-principles calculations. The boundary is found to fluctuate from snapshot to snapshot, and the feature of the simulated STM images differs distinctly from the observed one with a straightly extending honeycomb pattern of bright spots. Remarkably, statistical averages of the simulated images reproduce the observed feature. This study gives a warning of our tendency to relate STM images revealing clear arrangement of bright spots with some stable structure.