Formation of a heavy quasiparticle state in the two-band Hubbard model
Abstract
A realization of a heavy fermion state is investigated on the basis of a two-band Hubbard model. By means of the slave-boson mean-field approximation, it is shown that for the intermediate electron density, ne=1.5, the interband Coulomb repulsion U strongly emphasizes initially the 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 LiV2O4, an observed heavy fermion compound in a transition metal oxide.
- Publication:
-
Physical Review B
- Pub Date:
- August 2000
- DOI:
- 10.1103/PhysRevB.62.4403
- arXiv:
- arXiv:cond-mat/9912208
- Bibcode:
- 2000PhRvB..62.4403K
- Keywords:
-
- 71.27.+a;
- 71.10.Fd;
- Strongly correlated electron systems;
- heavy fermions;
- Lattice fermion models;
- Condensed Matter - Strongly Correlated Electrons
- E-Print:
- 5 pages, 4 figures, to be published in Phys. Rev. B