We used theoretical modeling to propose possible mechanisms of defect manipulation using a noncontact atomic force microscope (NC-AFM) on a generic oxide, $\mathrm{MgO}$. First, we simulated NC-AFM images of a Ca substitutional defect on the $\mathrm{MgO}$ surface aiming to help identify a site where tip polarity could be reliably identified, and as a possible target for manipulation. We conclude that controlled manipulation of substitutional ions on the $\mathrm{MgO}$ surface is not feasible due to the strength of the interaction within the surface. Secondly, we demonstrate that controlled manipulation of a charged surface $\mathrm{O}$ vacancy can be easily achieved via the reduction of a vacancy diffusion barrier by the tip electrostatic potential, which facilitates thermal vacancy diffusion.

• Received 23 December 2005

DOI:https://doi.org/10.1103/PhysRevB.73.245435