Static friction scaling of physisorbed islands: the key is in the edge

Abstract

The static friction preventing the free sliding of nanosized rare gas solid islands physisorbed on incommensurate crystalline surfaces is not completely understood. Simulations modeled on Kr/Pb(111) highlight the importance and the scaling behavior of the island's edge contribution to static friction.

New achievements in superlubricity from international workshop on superlubricity: fundamental and applications

“…It was demonstrated by simulation that rare gas islands on a metal indeed yield 0.25 < γ < 0.37, depending on the shape of the edge, as shown in Fig. 4 [18]. A fourth result emerged in a recently proposed frictional emulator, consisting of short cold ion N-member chains sliding in an optical lattice [19].…”

“…The sublinear scaling indicates superlubricity; residual friction is due to the island edge (Reproduced with permission from Ref. [18], Copyright 2014, Royal Society of Chemistry). which the superlubric drop of friction developed as N increased from the value of one.…”

Current trends in the physics of nanoscale friction

“…Until recently, it has been demonstrated or implied in a relatively small number of cases [29,[42][43][44][45][46]. There are now more evidences of superlubric behavior in cluster nanomanipulation [32,33,47], sliding colloidal layers [48][49][50], and inertially driven rare-gas adsorbates [51,52] (see Fig. 2).…”

A Markov state modeling analysis of sliding dynamics of a 2D model

“…The notable exception is however the second excitation, showing a forward jump. This marginal stick-slip behaviour is actually due to the weak but nonzero pinning caused by the island edge that hinder the entrance and exit of solitons [15], a subtle but real feature which in this case is efficiently and unbiasedly uncovered through this excitation.…”

“…Indeed, the latter correspond to internal relaxations of the island not associated with the collective sliding. In the specific case these corrections are related to the formation/destruction of incommensurate solitons induced on the island by the external potential [15].…”