Aubry transition with small distortions
arXiv:2405.01878 · doi:10.1103/PhysRevE.110.044206
Abstract
We show that when the Aubry transition occurs in incommensurately distorted structures, the amplitude of the distortions is not necessarily large as suggested by the standard Frenkel-Kontorova mechanical model. By modifying the shape of the potential in such a way that the mechanical force is locally stronger (i.e. increasing the nonlinearities), the transition may occur at a small amplitude of the potential with small distortions. A "phason" gap then opens, while the phonon spectrum resembles a standard undistorted spectrum at higher energies. This may explain the existence of pinned phases with small distortions as experimentally observed in charge-density waves.
10 pages, 8 figures, v2 added convergence figure + some exact results (app. B)