EFFECTS OF GEOMETRIC BERRY PHASE ON PERSISTENT CURRENTS IN LARGE-U ONE-DIMENSIONAL HUBBARD RINGS

By using the Bethe-Yang ansatz within the framework of the tight-bindi ng model, the ground state energy and the persistent current in one-di mensional Hubbard rings are calculated in the presence of an Aharonov- Bohm flux accompanied by a local magnetic field whose direction varies in space. Analytical results are obtained for large-U limit. It is in dicated that there usually exists no short periodicity for the ground state energy and persistent current due to the effect of the geometric Berry phase even for the case of infinite U. In a special case, the s hort periodicity retained in the sere-order approximation is broken do wn by taking into account the first-order energy correction for large but not infinite U. Moreover, it is found that in the strong-coupling limit, the electron-electron interaction suppresses the persistent cur rent, which is in agreement with other numerical calculations.