Yiming Song,1 Xiang Gao,2 Rémy Pawlak,1 Shuyu Huang,1,3 Antoine Hinaut,1 Thilo Glatzel,1 Oded Hod,2 Michael Urbakh,2 and Ernst Meyer1
1) Department of Physics, University of Basel, Basel 4056,
Switzerland.
2) 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.
3) Key Laboratory for Design and Manufacture of Micro-Nano Biomedical
Instruments, School of Mechanical Engineering, Southeast University,
Nanjing 211189, China.
Against conventional wisdom, corrugated grain boundaries in
polycrystalline graphene, grown on Pt(111) surfaces, are shown to
exhibit negative friction coefficients and non-monotonic velocity
dependence. Using combined experimental, simulation, and modeling
efforts, the underlying energy dissipation mechanism is found to be
dominated by dynamic buckling of grain boundary dislocation
protrusions. The revealed mechanism is expected to appear in a wide
range of polycrystalline two-dimensional material interfaces, thus
supporting the design of large-scale dry superlubric contacts.
