Monte Carlo study on the water bridge that produces the pull-off force in atomic force microscopy

A lattice gas model is implemented in simulating nanoscale water bridges condensed between a silicon nitride tip and a mica surface. We demonstrate how to calculate the pull-off force on the tip by using a Monte Carlo method. For four different tips, we checked how the width of a water bridge varies with respect to humidity. We also investigate the correlation between the bridge width and pull-off force.