24 citations · 151 across the 16 of their papers we have counts for
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cond-mat1997★ 12 cited
Spin Wave Instability of Itinerant Ferromagnet
Takuya Okabe
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 o…
cond-mat.str-el1997★ 5 cited
Hund's-Rule Coupling Effect in Itinerant Ferromagnetism
Takuya Okabe
We present a general model which includes the ferromagnetic Kondo lattice and the Hubbard model as special cases. The stability of the ferromagnetic state is investigated variation…
cond-mat1997★ 14 cited
Generalization of Gutzwiller Approximation
Takuya Okabe
We derive expressions required in generalizing the Gutzwiller approximation to models comprising arbitrarily degenerate localized orbitals.