Stochastic mechanism of energy dissipation in noncontact atomic force microscopy studied using molecular dynamics with Langevin boundary conditions

Based on the stochastic friction force theory of energy dissipation in non-contact atomic force microscopy (NC-AFM), we performed realistic molecular dynamics (MD) simulations on the MgO (001) surface to complement previous studies which only considered low frequency phonons in detail. We employed and calibrated Langevin boundary conditions to reduce effects due to the finite system size and thus to mimic an infinite lattice. The calculated dissipation energies are many orders of magnitude smaller than those observed experimentally and are similar to those calculated previously using simple analytical models. These findings suggest that this mechanism is not responsible for the observed energy dissipation.