An effective Hamiltonian for an extended Kondo lattice model and a possible origin of charge ordering in half-doped manganites

Abstract

An effective Hamiltonian is derived in the case of the strong Hund coupling and on-site Coulomb interaction by means of a projective perturbation approach. A physical mechanism for charge ordering in half-doped manganites (R_{0.5}X_{0.5}MnO_3) is proposed. The virtual process of electron hopping results in antiferromagnetic superexchange and a repulsive interaction, which may drive electrons to form a Wigner lattice. The phase diagram of the ground state of the model is presented at half doping. In the case of formation of Wigner lattice, we prove that spins of electrons are aligned ferromagnetically as well as that the localized spin background is antiferromagnetic. The influence of the on-site Coulomb interaction is also discussed.

6 pages ReTex with two figures To appear in Phys. Rev. B 59, (June 1, 1999)

References in corpus (5)

• Phase Separation in Electronic Models for Manganites
• Liquid-like spatial distribution of magnetic polarons revealed by neutron scattering in La{1-x}Ca{x}MnO3
• Electronic origin of magnetic and orbital ordering in insulating LaMnO_3
• Monte Carlo Simulations for the Magnetic Phase Diagram of the Double Exchange Hamiltonian
• Antiferromagnetism and phase separation in electronic models for doped transition-metal oxides

Cited by in corpus (3)

• Colossal Magnetoresistant Materials: The Key Role of Phase Separation
• Charge ordering and phase separation in the infinite dimensional extended Hubbard model
• The ground state phase diagram of the diluted ferromagnetic Kondo-lattice model