Spin-disordered ground state for a nearly half-filled Hubbard model

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Abstract

Following Nagaoka, the ground state of the large-U nearly half-filled Hubbard model is ferromagnetic. However, because of the anisotropic exchange energy JA, the physical Nagaoka ground state is nondegenerate and comprises a totally disordered spin state, i.e., a linear combination of all possible spin arrangements. For this ground state the susceptibility is Pauli-like but of a magnitude associated with a narrow band of width JA while the holons, i.e., the charge excitations, correspond to spinless fermions with a band of width 2zt. Associated with the spinon sector are very poorly defined spin waves, i.e., bosons, with a quadratic dispersion relation. These spin waves do not become soft at any finite temperature, rather, they soften as they approach the metal-insulator transition, i.e., as the number of holes n0 becomes small. Examined is the problem of constructing a mean-field slave-boson approach for the present problem.

Original languageEnglish (US)
Pages (from-to)8991-9002
Number of pages12
JournalPhysical Review B
Volume41
Issue number13
DOIs
StatePublished - 1990

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Hubbard model
Ground state
Bosons
Spin waves
magnons
ground state
boson fields
Metal insulator transition
Fermions
narrowband
sectors
bosons
fermions
energy transfer
insulators
magnetic permeability
metals
excitation
Temperature
temperature

ASJC Scopus subject areas

  • Condensed Matter Physics

Cite this

Spin-disordered ground state for a nearly half-filled Hubbard model. / Barnes, Stewart.

In: Physical Review B, Vol. 41, No. 13, 1990, p. 8991-9002.

Research output: Contribution to journalArticle

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