Magnon self energy in the correlated ferromagnetic Kondo lattice model: spin-charge coupling effects on magnon excitations in manganites

Abstract

Magnon self energy due to spin-charge coupling is calculated for the correlated ferromagnetic Kondo lattice model using a diagrammatic expansion scheme. Systematically incorporating correlation effects in the form of self-energy and vertex corrections, the expansion scheme explicitly preserves the continuous spin rotation symmetry and hence the Goldstone mode. Due to a near cancellation of the correlation-induced quantum correction terms at intermediate coupling and optimal band filling relevant for ferromagnetic manganites, the renormalized magnon energies for the correlated FKLM are nearly independent of correlation term. Even at higher band fillings, despite exhibiting overall non-Heisenberg behavior, magnon dispersion in the Γ-X direction retains nearly Heisenberg form. Therefore, the experimentally observed doping dependent zone-boundary magnon softening must be ascribed to spin-orbital coupling effects.

21 pages, 7 figures

References in corpus (12)

• Evolution of spin-wave excitations in ferromagnetic metallic manganites
• 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${}_3$ ($x=0.25,0.30$)
• Three--body Correlation Effects on the Spin Dynamics of Double--Exchange Ferromagnets
• Non--Heisenberg Spin Dynamics of Double-Exchange Ferromagnets with Coulomb Repulsion
• Spin waves in a band ferromagnet: spin-rotationally symmetric study with self-energy and vertex corrections
• Spin-charge coupling in a band ferromagnet: magnon-energy reduction, anomalous softening, and damping
• Spin dynamics in the diluted ferromagnetic Kondo lattice model
• Orbital fluctuations, spin-orbital coupling, and anomalous magnon softening in an orbitally degenerate ferromagnet
• Clustering induced suppression of ferromagnetism in diluted magnets
• Fermionic representation for the ferromagnetic Kondo lattice model -- diagrammatic study of spin-charge coupling effects on magnon excitations
• Spin-charge and spin-orbital coupling effects on spin dynamics in ferromagnetic manganites

Cited by in corpus (3)

• Magnon dressing by orbital excitations in ferromagnetic planes of K${}_2$CuF${}_4$ and LaMnO${}_3$
• Many-body theory of spin-current driven instabilities in magnetic insulators
• Role of atomic vacancies and second-neighbor antiferromagnetic-exchange coupling in a ferromagnetic nanoparticle