Multiscale model of the manipulation of single atoms on insulating surfaces using an atomic force microscope tip

We present the results of the multiscale modeling of the process of lateral manipulation of a Pd adatom adsorbed on the MgO (001) surface using a noncontact atomic force microscope (AFM) at finite temperature and in real time as a tip moves above the surface. We show that the stochastic motion of Pd adatoms can be controlled by localized forces from an oscillating tip and demonstrate how this can be achieved in practice. The energy barriers for manipulation as a function of tip position in three dimensions above the surface are determined from atomistic calculations and then used in a kinetic Monte Carlo algorithm to determine the evolution of the system at a finite temperature and in real time for a realistic trajectory of the tip, which is in turn governed by a complete numerical simulation of the instrument including the response of the feedback loops. We can then predict the probability of a successful manipulation event for a given procedure. The multiscale modeling technique developed in this work can be used to determine optimum experimental protocols for controlled single-atom manipulation using noncontact AFM.