Enhancement of charge ordering by the zeeman effect in one-dimensional molecular conductors

The effects of an external magnetic field on the charge-ordered state are investigated within the one-dimensional extended Hubbard model with a quarter-filled band. We find that the external magnetic field leads to a coexistent state with three order parameters, i.e., the charge ordering, the uniform, and the staggered magnetic moments. In addition, the amplitude of the charge ordering is shown to be enhanced by the magnetic field.