Avalanche Dynamics in Stick-Slip Cutting of Molybdenum Disulfide.

We have investigated nanoscale wear on multilayered MoS2, the flagship transition metal dichalcogenide, by elastically driving sharp diamond tips under normal loads sufficient to induce in-plane fracture. The accompanying friction and the resulting wear structures are first characterized by atomic force microscopy (AFM), revealing a stick-slip regime that drives progressive exfoliation of MoS2 chips. At high normal forces, the slip phase displays hallmark signatures of avalanche dynamics, observed for the first time at the nanoscale, evidenced by a Generalized Extreme Value distribution of friction force drops. The AFM characterization is corroborated by molecular dynamics simulations, which reproduce experimental trends and uncover atomistic details of the wear process, including local amorphization, layer curving, and the involvement of distinct dissipative channels. Notably, it appears that only one-fifth of the energy input into the system is used to damage the MoS2 surface irreversibly. These results offer new insight into the physical mechanisms governing friction and wear in layered solids and provide a framework for precision cutting and nanomachining in van der Waals materials, relevant to next-generation devices at sub-micrometer scales.