The CE phase of La_(1-x)CaxMnO_3 is stable for x>0.5 and displays long-range magnetic, charge, and orbitalorders. The magnetic order of the Mn spins arises from the competition of the superexchange and double-exchange interactions and the checkerboard charge and the orbital order is the consequence of the Jahn-Tellercoupling of the eg orbitals to the lattice. Using a mean-field slave-boson approach for the eg electrons in twoorbitals per site with excluded multiple occupancy and Hund's rule coupling between the e_gandt_(2g)states, weobtain the tight-binding band structure of the CE phase. The unit cell of the CE phase consists of 16 sites. The32 eg bands in the Brillouin zone are grouped into two sets of 16 bands separated by a charge order gap. Thephase diagram including the A, B, C, CE, and G phases reproduces the phase sequence observed inLa_(1-x)Ca_xMnO_3.
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