BINDING ENERGY OF THE SELF-TRAPPED MAGNETIC POLARON: EFFECT OF THE INTRA-SUBLATTICE ELECTRON HOPPING

Abstract

We study the energetic stability of the self-trapped magnetic polaron in an antiferromagnetic lattice of localized spins, including the effects of the intra-sublattice hopping which allows electron transfer within the same magnetic sublattice. The model consists of an itinerant electron moving in a one-dimensional antiferromagnetic lattice of localized spins. In addition to the first and the second neighbor electron hopping, terms describing the superexchange between the localized spins as well as the Hund's-rule coupling between the electron and the localized spins are included in the model Hamiltonian. The ground-state energy of the self-trapped polaron with the resulting ferromagnetic core region is compared with the energy of the propagating state in the antiferromagnetic lattice. We find the magnetic polaron to be self-trapped for all values of the Hamiltonian parameters, although the intra-sublattice hopping substantially reduces the polaron binding energy.