Using the ability of the noncontact atomic force microscopy (NC-AFM) to image and perturb the Si(001) dimer configuration, we investigate the influence of surface stress around an SA step of Si(001) on the buckled dimer at 5 K. The NC-AFM first detected the different buckled dimer phases between the terraces: asymmetric c(4×2) phase in the upper terrace and symmetric p(2×1) one in the lower terrace appeared in both topographic and dissipation images. In addition, we found, for the first time, the dimers by the step in the upper terrace compress by 0.036±0.013 along dimer bond direction from the averaged profile analysis of the images. Variation in the surface dimer structure reflected by the surface stress was demonstrated from the dissipation image analysis, which points to the possible exploration of the surface stress by means of NC-AFM.
