We present a mean-field theory of charge, orbital, and spin ordering in manganites at 50% and 0% dopings by considering Jahn-Teller interaction, nearest-neighbor repulsion, and no single-site double occupancy. For spinless fermions, we show that Jahn-Teller distortion and charge-orbital ordering occur simultaneously. In our two-dimensional model at 50% doping, for small nearest-neighbor repulsion the system is orbitally polarized while for larger repulsion the system undergoes CE type ordering.

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... As for the 0% doping case, the ground state is orbitally antiferromagnetic. Upon including spin degree of freedom, at both 50% and 0% dopings the ordering remains the same at small antiferromagnetic coupling between adjacent core spins.