Ratchet effect in solids: Defect transport driven by biharmonic forces

Abstract

Interstitials and vacancies, in one-dimensional lattices, are point defects that can be modelled by means of kinks or antikinks in a discrete Frenkel-Kontorova model, with a sine-Gordon on-site potential. The properties of kinks and antikinks are the same if a harmonic interaction potential is considered. The ratchet properties of these defects in the above mentioned context has been studied by Zolotaryuk and Salerno when the system is driven by a biharmonic field. The properties of these solutions are strongly altered when an anharmonic interaction potential is introduced in the model, as the Peierls-Nabarro barrier is higher for antikinks than for kinks. The aim of this poster is to show the effects of the anharmoniciy of the interaction potential in the properties of kinks and antikinks focusing in the assymetry between the properties of these two species of topological solitons