Intrinsic Localized Modes in Antiferromagnetic Chains with Dzyaloshinsky-Moriya Interaction

In this paper, we present an analytical study on intrinsic localized spin-wave modes in antiferromagnetic chains with Dzyaloshinsky-Moriya interaction in semiclassical limit. By means of the method of multiple scales combined with a quasi-discreteness approximation, the nonlinear Schrödinger equation is derived for the conherent-state amplitude. It is found that a bright stationary intrinsic localized spin-wave mode can appear below the linear spin-wave spectrum. Besides, we show that the antiferromagnetic chain can produce a dark intrinsic localized spin-wave mode, namely, nonpropagating kink, which is a typical nonlinear resonant mode.