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Friction depends on speed

AFM tip on a monolayer of molybdenum disulfide on a gold surface

Researchers use an AFM to investigate friction on the nanometer scale over a monolayer of molybdenum disulfide on a gold surface. (Image: Department of Physics, University of Basel)

A team of researchers from the SNI network has recently shown that, on the nanometer scale, frictional forces depend on speed. The scientists from Professor Ernst Meyer's team at the Department of Physics (University of Basel) moved the tip of an atomic force microscope (AFM) over a monolayer of molybdenum disulfide on a gold surface. They found that the friction between the AFM tip and the surface decreases over a broad speed range of 10 to 100 nanometers per second. These results, recently published in Physical Review Letters, deviate from the classic Coulomb law, which describes the independence of friction from velocity.

Original publication: https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.133.136201