Physical dissipation mechanisms in non-contact atomic force microscopy

Abstract

Using realistic molecular dynamics simulations on the MgO(001) surface we show that thefriction coefficient and dissipation energies due to the stochastic friction force mechanismare much smaller than observed experimentally in close agreement with previous analyticalmodels. Therefore, the method is generalized by including a single soft vibrational mode atthe surface. Using methods of non-equilibrium statistical mechanics, we derive an equationof motion for the tip interacting with the soft mode. It is shown that this methodenables the simultaneous description of both stochastic friction and adhesion.