Eur. Phys. J. B (2013) 86: 314
https://doi.org/10.1140/epjb/e2013-40214-1

Regular Article

Quasiparticle states in the antiferromagnetic phase of double exchange systems

¹ Department of Physics, Chiba University, 263-8522 Chiba, Japan
² Karlsruhe Institut of Technology, Institut für Festkörperphysik, 76021 Karlsruhe, Germany
³ Institute for Low Temperature and Structure Research, P.O. Box 1410, 50-950 Wrocław 2, Poland

^a e-mail: robert.eder@kit.edu

Received: 14 March 2013
Received in final form: 25 April 2013
Published online: 8 July 2013

Abstract

We present a theory for the quasiparticle band structure in the antiferromagnetic phase of a Kondo-lattice Hamiltonian with ferromagnetic Hund’s rule exchange between conduction electrons and localized spins and antiferromagnetic superexchange between localized spins. The quantum mechanical character of the localized spins is kept and no semiclassical approximation is made. Comparison of the obtained quasiparticle spectrum with exact diagonalization of finite clusters shows good agreement. Ferromagnetic polarization is energetically favorable only for very weak superexchange and small conduction electrons density. We discuss localized states where a conduction electron is trapped near a misalligned localized spin as well as superlattices of such misalligned spins.