Charge stacking in the half-doped manganites

The stability of the charge-stacked structure vis-à-vis the charge-alternate structure in the half-doped manganites is studied with a model that includes electronic kinetic energy, onsite and intersite Coulomb interactions, the Jahn–Teller energy, and the antiferromagnetic superexchange between the manganese core spins. It is shown that for a single zigzag chain, the electronic kinetic energy stabilizes the standard chain, with Mn at the bridge site and Mn at the corner site, over the ‘‘reversed’’ zigzag chain with the two Mn valences interchanged. The electronic kinetic energy and magnetic interactions stabilize the three-dimensional charge-stacked structure, while a large intersite Coulomb interaction V>Vc would stabilize the charge-alternate structure. It is argued that the magnitude of V is small enough that the charge-stacked structure is stabilized in the half-doped manganites such as La1/2Ca1/2MnO3 . © 2002 American Institute of Physics. @DOI: 10.1063/1.1456435#