Structural and Chemical Evolution of the Near-Apex Region of an Atomic Force Microscope Tip Subject to Sliding

Atomic force microscopy and molecular dynamics simulation are used to study the nanoscale wear of a silicon dioxide tip sliding on a copper substrate. Wear is characterized in terms of structural and chemical evolution of the system where the latter is possible experimentally using atom probe tomography of the slid tips. Comparison of the experimentally observed and simulation-predicted wear reveals that adhesive wear is dominant in the short sliding distances of the simulation at any applied load, while the sliding distances in the experiments are long enough to observe load-induced transitions between adhesive-dominated and abrasive-dominated wear.