2010/07/05 by Fusayoshi J. Ohkawa, Ohkawa, Fusayoshi J.
Physics and Astronomy · #Advanced Condensed Matter Physics #FOS: Physical sciences #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #Strongly Correlated Electrons (cond-mat.str-el)
paper · pdf · doi:10.48550/arxiv.1007.0764
openalex publication_date 2010/07/05 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The Hubbard model in the Heisenberg limit is studied by Kondo-lattice theory. The Kondo temperature TK or kBTK, which is an energy scale of low-energy local quantum spin fluctuations, is enhanced by the resonating valence bond (RVB) mechanism, so that TK≃ TMF/(2D), where TMF is the Neel temperature in the mean-field approximation of the corresponding Heisenberg model and D is the spatial dimensionality. Electrons certainly behave as localized spins at T≫ TK, but they are still itinerant at T≪ TK unless an antiferromagnetic complete gap opens. When the Neel temperature TN is so high that TN≫ TMF/(2D), magnetism is prototypic local-moment magnetism. When TN is so low that TN ≪ TMF/(2D) because of low dimensionality or frustration, magnetism is itinerant-electron magnetism of an almost spin liquid, i.e., a normal Fermi liquid or a Tomonaga-Luttinger liquid in which the spectral weight of single-particle excitations is almost vanishing. The spin susceptibility has a temperature and wave-number dependence characteristic of itinerant-electron magnetism. This type of itinerant-electron magnetism must also be possible in the Heisenberg model.