Visualization of thermally fluctuating surface structure in noncontact atomic-force microscopy and tip effects on fluctuation:: Theoretical study of Si(111)-(√(3)over-bar x √(3)over-bar)-Ag surface -: art. no. 046106

We investigated noncontact atomic-force microscopy (NC-AFM) images of a thermally fluctuating surface structure together with tip effects based on the first-principles electronic state calculation. As an example the Si(111)-(root3 x root3)-Ag (root-3-Ag) surface is studied. We have succeeded in theoretically visualizing the thermal fluctuation of the root3-Ag surface at room temperature, and in reproducing the observed NC-AFM image for the first time. Further, the pinning effect of the thermal fluctuation of the root3-Ag surface by the tip is clarified, which shows a novel ability of NC-AFM to modify the surface structure.