Fermionic representation for the ferromagnetic Kondo lattice model -- diagrammatic study of spin-charge coupling effects on magnon excitations

Abstract

A purely fermionic representation is introduced for the ferromagnetic Kondo lattice model which allows conventional diagrammatic tools to be employed to study correlation effects. Quantum 1/S corrections to magnon excitations are investigated using a systematic inverse-degeneracy expansion scheme which incorporates correlation effects in the form of self-energy and vertex corrections, while explicitly preserving the continuous spin-rotation symmetry. Magnon self-energy is studied in the full range of interaction strength, and shown to result in strong magnon damping and anomalous softening for zone boundary modes, which accounts for several zone-boundary anomalies observed in recent spin-wave measurements of ferromagnetic manganites.

16 pages, 9 figures

References in corpus (5)

• Magnons in Ferromagnetic Metallic Manganites
• Spin waves throughout the Brillouin zone and magnetic exchange coupling in ferromagnetic metallic manganites La${}_{1-x}$Ca${}_x$MnO${}_3$ ($x=0.25,0.30$)
• Non--Heisenberg Spin Dynamics of Double-Exchange Ferromagnets with Coulomb Repulsion
• Spin dynamics in the diluted ferromagnetic Kondo lattice model
• Quantum and thermal fluctuations in a two-dimensional correlated band ferromagnet -- Goldstone-mode preserving investigation with self-energy and vertex corrections

Cited by in corpus (1)

• Spin-charge coupling in a band ferromagnet: magnon-energy reduction, anomalous softening, and damping