1. Atomic-scale mechanisms of friction Udo D
Atomic-scale mechanisms of friction Udo D. Schwarz, Department of Mechanical Engineering, Yale University
We conducted a series of experiments that were aimed at gaining insight into the fundamental mechanisms of friction at the atomic scale. The experiments were carried out applying new experimental approaches using scanning force microscopes operated in ultrahigh vacuum. Two goals were reached:
We succeeded in measuring the force acting between the probe tip and a graphite surface in all three dimensions with picometer accuracy. This allows for the first time the study of lateral forces with sub-atomic resolution.
In collaboration with the University of Münster, Germany, we studied the contact area dependence of friction by manipulating antimony nanoparticles deposited on graphite. For the first time, superlubricity of extended nanocontacts could be demonstrated.
Lateral forces on graphite measured with sub-atomic resolution using three-dimensional dynamic force spectroscopy. Image size: 4 Å  4 Å.
Lateral forces of Sb nanoparticles translated on graphite in ultrahigh vacuum. Vanishing friction (red data points) indicates superlubricity.