A vacancy defect is described by a Frenkel--Kontorova model with a discommensuration. This vacancy can migrate when interacts with a moving breather. We establish that the width of the interaction potential must be larger than a threshold value in order that the vacancy can move forward. This value is related to the existence of a breather centred at the particles adjacent to the vacancy.
@article{arxiv.nlin/0306039,
title = {Influence of moving breathers on vacancies migration},
author = {J. Cuevas and C. Katerji and J. F. R. Archilla and J. C. Eilbeck and F. M. Russell},
journal= {arXiv preprint arXiv:nlin/0306039},
year = {2007}
}