Intrinsic localized spin wave modes in easy-axis antiferromagnetic chains

Two types of intrinsic localized spin wave modes are found in perfect antiferromagnetic chains of classical spins with on-site easy-axis anisotropy: the amplitude is either double or single peaked. In the small spin deviation limit, both types become identical envelope solitons. The degree of localization increases as either the maximum spin deviation or the ratio of the anisotropy constant to the exchange coupling constant increase. However, only the single peaked intrinsic localized mode is stable with regard to a noise perturbation.