Magnetic polarons in layered antiferromagnetic systems

Abstract

The energy and stability conditions are found for free ferromagnetic polarons (ferrons) in the antiferromagnetic semiconductors with a layered magnetic structure. Unlike a similar problem for the staggered antiferromagnets, solved long ago, this geometrically different problem was not considered yet. In particular, the difference between these two problems consists in the fact that the ferromagnetic region, which traps the charge carrier, is well defined for the staggered structure, and is not for the layered structure. The latter is due to ferromagnetic planes inherent in this structure. It is established that, nevertheless, the ferromagnetic region is almost spherical for large ferrons. The De Gennes single-spin magnetic polaron is unstable at realistic values of parameters. The energy and magnetic moment of the ferron bound to a donor or acceptor are calculated for the case of the double exchange.