Kink ratchets in the Klein-Gordon lattice free of the Peierls-Nabarro potential

TL;DR

This paper introduces a discrete Klein-Gordon model with asymmetric potential supporting kinks free of the Peierls-Nabarro potential, and investigates their unique ratchet dynamics under harmonic AC driving, contrasting with conventional models.

Contribution

The study constructs a new Klein-Gordon lattice model supporting PNp-free kinks and analyzes their distinct ratchet behavior under AC driving, highlighting differences from traditional models.

Findings

PNp-free kinks exhibit different ratchet dynamics from conventional kinks.

Discreteness parameter has little effect on AC-induced acceleration of PNp-free kinks.

No significant influence of lattice discreteness on kink ratchet acceleration was observed.

Abstract

A discrete Klein-Gordon model with asymmetric potential that supports kinks free of the Peierls-Nabarro potential (PNp) is constructed. Undamped ratchet of kinks under harmonic AC driving force is investigated in this model numerically and contrasted with the kink ratchets in the conventional discrete model where kinks experience the PNp. We show that the PNp-free kinks exhibit ratchet dynamics very much different from that reported for the conventional lattice kinks which experience PNp [see, e.g., Phys. Rev. E {\bf 73}, 066621 (2006)]. Particularly, we could not observe any significant influence of the discreteness parameter on the acceleration of PNp-free kinks induced by the AC driving.