Chiral edge soliton in nonlinear Chern systems

TL;DR

This paper investigates how nonlinearity affects chiral edge states in a Chern insulator, revealing the formation of chiral edge solitons and a self-trapping transition driven solely by initial conditions.

Contribution

It introduces the concept of chiral edge solitons in nonlinear Chern systems and demonstrates control of edge state dynamics through initial conditions.

Findings

Formation of chiral edge solitons due to nonlinearity

Observation of a self-trapping transition at higher nonlinearity

Edge state propagation can be controlled without altering the sample

Abstract

We study the effect on the chiral edge states by including a nonlinearity to a Chern insulator which has two chiral edge states with opposite chiralities. We explore a quench dynamics by giving a pulse to one site on an edge and analyzing the time evolution of a wave packet. Without the nonlinearity, an initial pulse spreads symmetrically and diffuses. On the other hand, with the nonlinearity present, a solitary wave is formed by the self-trapping effect of the nonlinear term and undergoes a unidirectional propagation along the edge, which we identify as a chiral edge soliton. A further increase of the nonlinearity induces a self-trapping transition, where the chiral wave packet stops its motion. It is intriguing that the nonlinearity is controlled only by changing the initial condition without changing a sample.