Spin Wave Instability of Itinerant Ferromagnet

Abstract

We show variationally that instability of the ferromagnetic state in the Hubbard model is largely controlled by softening of a long-wavelength spin-wave excitation, except in the over-doped strong-coupling region where the individual-particle excitation becomes unstable first. A similar conclusion is drawn also for the double exchange ferromagnet. Generally the spin-wave instability may be regarded as a precursor of the metal-insulator transition.

11 pages, 8 figures

References in corpus (2)

• Lattice dependence of saturated ferromagnetism in the Hubbard model
• Hund's-Rule Coupling Effect in Itinerant Ferromagnetism

Cited by in corpus (9)

• Nucleon and hadron structure changes in the nuclear medium and impact on observables
• Density-of-states picture and stability of ferromagnetism in the highly-correlated Hubbard model
• Three--body Correlation Effects on the Spin Dynamics of Double--Exchange Ferromagnets
• Non--Heisenberg Spin Dynamics of Double-Exchange Ferromagnets with Coulomb Repulsion
• Magnetic fluctuations and self--energy effects in two--dimensional itinerant systems with van Hove singularity of electronic spectrum
• Disorder Induced Ferromagnetism in Restricted Geometries
• Influence of Spin Wave Excitations on the Ferromagnetic Phase Diagram in the Hubbard-Model
• Ferromagnetism, spiral magnetic structures and phase separation in the two-dimensional Hubbard model
• Ferromagnetism in the Highly-Correlated Hubbard Model