Modeling study of microscopic sliding on irregular substrates

In connection with microscopic solid friction phenomena, we study the underdamped dynamics of a driven Frenkel–Kontorova chain subject to a substrate potential defined by the sum of two sinusoidal function with different periodicity.We simulate microscopic sliding over quasiperiodic and multiple-well (periodic) substrates. We comment on thenature of the particle dynamics in the vicinity of the pinning–depinning transition point and consider the role played bythe coverage variable on the depinning mechanism. We also investigate on the different nonlinear excitations formingduring sliding and characterizing the dynamical states observed at different strengths of the imposed driving. Thedependence of the static friction on the ratio of the model interaction strengths is analyzed.