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arXiv · 0710.2828

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

Sudhakar Pandey·Subrat Das·Bhaskar Kamble·Saptarshi Ghosh·Dheeraj Singh·Rajyavardhan Ray·Avinash Singh
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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.

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Sudhakar Pandey, Subrat Das, Bhaskar Kamble, Saptarshi Ghosh, Dheeraj Singh, Rajyavardhan Ray, Avinash Singh. 2007-10-15. Fermionic representation for the ferromagnetic Kondo lattice model -- diagrammatic study of spin-charge coupling effects on magnon excitations. https://doi.org/10.1103/physrevb.77.134447

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