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Formation of heavy quasiparticle state in two-band Hubbard model

H. Kusunose·S. Yotsuhashi·K. Miyake
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Abstract

A realization of heavy fermion state is investigated on the basis of two-band Hubbard model. By means of the slave-boson mean-field approximation, it is shown that for the intermediate electron density, n_e=1.5, the inter-band Coulomb repulsion U strongly emphasizes initially small difference between bands, and easily stabilizes integral valence in the lower band. As a result, a strong renormalization takes place in the lower band and the mixing strength between two bands. It gives rise to a sharp peak at the Fermi level in the quasiparticle density of states, as that obtained in the periodic Anderson model. In contrast to a simple insight that the Hund's-rule coupling J reduces the characteristic energy, it turns out to be almost irrelevant to the renormalization for J<U. The required conditions are suitable for LiV_2O_4, the first observed heavy fermion compound in transition metal oxide.

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H. Kusunose, S. Yotsuhashi, K. Miyake. 2000-05-10. Formation of heavy quasiparticle state in two-band Hubbard model. https://doi.org/10.1103/physrevb.62.4403

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