Jahn-Teller distortion induced charge ordering in the CE phase of manganites

The charge ordering of CE phase in half-doped manganites is studied, based on an argument that the charge ordering is caused by the Jahn-Teller distortions of MnO6 octahedra rather than Coulomb repulsion between electrons. The quantitative calculation on the ferromagnetic zigzag chain as the basic structure unit of the CE phase using a two-orbital model is performed, and it is shown that the charge disproportion of Mn cations in the charge-ordered CE phase is less than 13%. In addition, we predict the negative charge-disproportion once the Jahn-Teller effect is weak enough.