Interaction of moving discrete breathers with vacancies

Abstract

In this paper a Frenkel–Kontorova model with a nonlinear int eraction potential is used to describe a vacancy defect in a crystal. According t o recent numerical results [Cuevas et al . Phys. Lett. A 315, 364 (2003)] the vacancy can migrate when it interacts with a moving breather. We study more thoroughl y the phenomenology caused by the interaction of moving breathers with a single v acancy and also with double vacancies. We show that vacancy mobility is strongly correlated with the existence and stability properties of stationary breather s centered at the particles adjacent to the vacancy, which we will now call vacancy breat hers.