J Cuevas, PG Kevrekidis, DJ Frantzeskakis and AR Bishop (pdf copy 1.7 Mb)

Abstract:

We consider polarons in models of coupled electronic and vibrational degrees of freedom, in the presence of a soft nonlinear inter-particle potential (Morse potential). In particular, we focus on a a bound state of a polaron with a breather, a so-called polarobreather. We analyze the existence of these states based on frequency resonance conditions and illustrate their stability using Floquet spectrum techniques. Multi-site solutions of this type are also obtained both in the stationary case (bond-centered and twisted polarons) and in the breathing case (bond-centered and twisted polarobreathers). For all the branches examined, the dynamical evolution of instabilities pertinent to the corresponding solutions are also briefly discussed. Finally, a different branch of so-called phantom polarobreathers is also demonstrated.

Phys. Rev. B 74: 064304/1-12, August 2006.
doi:10.1103/PhysRevB.74.064304
Selected by the Virtual Journal of Biological Physics Research    12(5) (Statistical and Nonlinear Physics) September 1, 2006.