Enhanced ferromagnetism from electron-electron interactions in double exchange type models

Abstract

The magnetic properties of a variety of materials with promise for technological applications have been described by models in which fermions are coupled to local moment spins. Monte Carlo studies of such models usually ignore electron-electron interactions, even though the energy scale corresponding to these interactions may be comparable to or larger than other relevant energy scales. In this work we add on-site interactions between fermions to the double exchange model which we study with a Monte Carlo scheme in which temporal fluctuations of local moment spins are fully accounted for and electron-electron interactions are treated at a mean field level. We show that when the number of fermions is considerably less than the number of local moments even moderate interactions can lead to significant enhancement of ferromagnetism and the Curie temperature.

4 + epsilon pages, 3 figures

References in corpus (23)

• Colossal Magnetoresistant Materials: The Key Role of Phase Separation
• Phase Separation in Electronic Models for Manganites
• Colossal Effects in Transition Metal Oxides Caused by Intrinsic Inhomogeneities
• Interlayer coupling in ferromagnetic semiconductor superlattices
• Monte Carlo Study of Ferromagnetism in (III,Mn)V Semiconductors
• Hybrid Monte Carlo algorithm for the Double Exchange Model
• Modelling colossal magnetoresistance manganites
• A Monte Carlo Method for Fermion Systems Coupled with Classical Degrees of Freedom
• Global versus Local Ferromagnetism in a Model for Diluted Magnetic Semiconductors Studied with Monte Carlo Techniques
• Monte Carlo simulations of an impurity band model for III-V diluted magnetic semiconductors
• Monte Carlo Simulations for the Magnetic Phase Diagram of the Double Exchange Hamiltonian
• Single-Band Model for Diluted Magnetic Semiconductors: Dynamical and Transport Properties and Relevance of Clustered States
• Metal-Insulator Transition and Ferromagnetism in Diluted Magnetic Semiconductors
• Impurity-Semiconductor Band Hybridization Effects on the Critical Temperature of Diluted Magnetic Semiconductors
• Influence of Nearest-Neighbor Coulomb Interactions on the Phase Diagram of the Ferromagnetic Kondo Model
• Double Exchange Model for Magnetic Hexaborides
• Long Range Coulomb Interactions and Nanoscale Electronic Inhomogeneities in Correlated Oxides
• Positional Disorder, Spin-Orbit Coupling and Frustration in GaMnAs
• Effects of the On-Site Coulomb Repulsion in Double Exchange Magnets
• Combined approach of density functional theory and quantum Monte Carlo method to electron correlation in dilute magnetic semiconductors
• Large-Scale Monte Carlo Study of a Realistic Lattice Model for Ga_(1-x)Mn_xAs
• Disorder, spin-orbit, and interaction effects in dilute ${\mathrm{Ga}}_{1-x}{\mathrm{Mn}}_x\mathrm{As}$
• New Correlated Model of Colossal Magnetoresistive Manganese Oxides