Stabilization of magnetic polarons in antiferromagnetic semiconductors by extended spin distortions

Abstract

We study the problem of a magnetic polaron in an antiferromagnetic semiconductor (ferron). We obtain an analytical solution for the distortion produced in the magnetic structure of the d-spins due to the presence of a charge carrier bound to an impurity. The region in which the charge carrier is trapped is of the order of the lattice constant (small ferron) but the distortion of the magnetic structure extends over much larger distance. It is shown that the presence of this distortion makes the ferron more stable, and introduces a new length scale in the problem.

5 pages, 1 figure, RevTex 4, submitted to PRB; v2: one reference added, minor changes in the experiment discussion; v3: minor changes in text