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arXiv · 0804.0680

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

Sudhakar Pandey·Avinash Singh
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Abstract

The effects of correlation-induced coupling between spin and charge fluctuations on spin-wave excitations in a band ferromagnet are investigated by including self-energy and vertex corrections within a systematic inverse-degeneracy expansion scheme which explicitly preserves the Goldstone mode. Arising from the scattering of a magnon into intermediate spin-excitation states (including both magnon and Stoner excitations) accompanied with charge fluctuations in the majority spin band, this spin-charge coupling results not only in a substantial reduction of magnon energies but also in anomalous softening and significant magnon damping for zone-boundary modes lying within the Stoner gap. Our results are in good qualitative agreement with recent spin-wave excitation measurements in colossal magneto-resistive manganites and ferromagnetic ultrathin films of transition metals.

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Sudhakar Pandey, Avinash Singh. 2008-04-04. Spin-charge coupling in a band ferromagnet: magnon-energy reduction, anomalous softening, and damping. https://doi.org/10.1103/physrevb.78.014414

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