Negative Friction Coefficients in Superlubric Graphite-Hexagonal Boron Nitride Heterojunctions
arXiv:1902.08067 · doi:10.1103/PhysRevLett.122.076102
Abstract
Negative friction coefficients, where friction is reduced upon increasing normal load, are predicted for superlubric graphite-hexagonal boron nitride heterojunctions. The origin of this counterintuitive behavior lies in the load-induced suppression of the moiré superstructure out-of-plane distortions leading to a less dissipative interfacial dynamics. Thermally induced enhancement of the out-of-plane fluctuations leads to an unusual increase of friction with temperature. The highlighted frictional mechanism is of a general nature and is expected to appear in many layered material heterojunctions.
34 pages, 16 figures, (file includes Supplemental Material)