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Spin Wave Instability of Itinerant Ferromagnet

Takuya Okabe
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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.

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Takuya Okabe. 1997-07-29. Spin Wave Instability of Itinerant Ferromagnet. https://doi.org/10.1103/physrevb.57.403

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