Phonon scattering by discrete breather in one-dimensional nonlinear lattices with symmetry in potential functions

Abstract

Discrete breathers are spatially localized time-periodic solutions in nonlinear lattices. We study the scattering of small amplitude phonons by a discrete breather in two types of one-dimensional nonlinear lattices, which are called the pairwise interaction symmetric lattice (PISL) and the Umklapp-free lattice (UFL). Each lattice has its own particular symmetry in the potential function and is known to exhibit quite anomalous heat transport: the PISL exhibits an almost ballistic transport;the UFL the ballistic transport implying no thermal resistance. We numerically calculate the transmission and reflection rates of a phonon wave packet as a function of the wavenumber. It is shown that almost perfect transmission occurs in the PISL while almost perfect reflection in the UFL.