Abstract
The diamagnetic susceptibility of the infinity-U Hubbard model is investigated in one and two dimensions. In one dimension, it is shown that the charge current flowing in the ground state of a ring threaded by a flux tube vanishes in the thermodynamic limit. Similar behavior is inferred for the single-hole problem on a two-dimensional square lattice, from exact-diagonalization results on small clusters. Effectively the applied field is canceled by an induced fictitious field and the susceptibility vanishes. Our results suggest that the Nagaoka ferromagnet is unstable with respect to a low-spin state, level crossing to a chiral spin state occurring at infinitesimally small diamagnetic coupling.
Original language | English |
---|---|
Pages (from-to) | 8349-8352 |
Number of pages | 4 |
Journal | Physical Review B |
Volume | 44 |
Issue number | 15 |
DOIs | |
Publication status | Published - 15 Oct 1991 |