  The Berry phase of a bipartite system described by a Heisenberg XXZ model
driven by a one-site magnetic field is investigated. The effect of the
Dzyaloshinski-Moriya (DM) anisotropic interaction on the Berry phase is
discussed. It is found that the DM interaction affects the Berry phase
monotonously, and can also cause sudden change of the Berry phase for some weak
magnetic field cases.
