Department of Physical Chemistry, School of Chemistry, The Raymond and Beverly Sackler Faculty of Exact Sciences and The Sackler Center for Computational Molecular and Materials Science, Tel Aviv University, Tel Aviv 6997801, Israel.
Phys Rev Lett. 2019 Feb 22;122(7):076102. doi: 10.1103/PhysRevLett.122.076102.
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.
负摩擦系数，即摩擦力随着法向载荷的增加而减小，被预测存在于超润滑石墨-六方氮化硼异质结中。这种违反直觉的行为源于载荷诱导的莫尔超结构面外变形的抑制，从而导致界面动力学的能量耗散减少。热诱导的面外涨落增强导致摩擦力随温度的异常增加。突出的摩擦机制具有普遍性，预计会出现在许多层状材料异质结中。
