Abstract
We have performed ab initio simulations of atomic force microscopy (AFM) image formation in the non- contact regime for the surface. We use classical perturbation theory to compute the experimentally measured frequency shifts and the density-functional theory to describe the tip-surface interactions. Particular attention is paid to the effect of tip morphology. We consider three different tip apexes: Si, In, and P with the concomitant differences in the dangling-bond states of the tip. We find that the Si and In apexes produce qualitatively similar results, where the anion (P) sublattice shows up as protrusions. Qualitatively different results are obtained with the P apex which produces the largest apparent AFM corrugation and a complete reversal of the surface corrugation with respect to both the Si and In apexes as well as with respect to the real geometric corrugation.
- Received 17 July 2000
DOI:https://doi.org/10.1103/PhysRevB.63.245324
©2001 American Physical Society