Charge Ordering Under a Magnetic Field in the Extended Hubbard Model

We study the charge ordering behavior under a magnetic field $H$ in the extended Hubbard model within the coherent potential approximation. At quarter filling, for small $H$ we find that the relative variation of critical temperature is quadratic with the coefficient ${\alpha}$ smaller than the one for conventional spin-Peierls systems. For intermediate field, a melting of the charge ordering on decreasing temperature under fixed $H$ at various band filling is found.