A new type of bound magnetic polaron state: the formation of long-range spin distortions

TL;DR

This paper investigates a novel bound magnetic polaron state in antiferromagnetic materials, revealing long-range spin distortions that decay with distance and are energetically favorable, expanding understanding of magnetic polaron structures.

Contribution

It introduces a new type of bound magnetic polaron with extended spin distortions in 2D and 3D models, highlighting their decay behavior and energetic stability.

Findings

Long-range spin distortions decay as 1/r^2 in 2D and 1/r^4 in 3D.

Magnetic polarons have smaller core magnetization than saturation.

The new polaron state is energetically more favorable than traditional models.

Abstract

The structure of bound magnetic polarons in an antiferromagnetic matrix is studied in the framework of two-dimensional (2D) and three-dimensional (3D) Kondo-lattice models in the double exchange limit (J_H >> t). The conduction electron is bound by a nonmagnetic donor impurity and forms a ferromagnetic core of the size about the electron localization length (bound magnetic polaron). We find that the magnetic polaron produces rather long-range extended spin distortions of the antiferromagnetic background around the core. In a wide range of distances, these distortions decay as 1/r^2 and 1/r^4 in 2D and 3D cases, respectively. In addition, the magnetization of the core is smaller than its saturation value. Such a magnetic polaron state is favorable in energy in comparison to usually considered one (saturated core without extended distortions).