0 Superexchange in the quarter - filled two - leg ladder system NaV
نویسنده
چکیده
A theory of superexchange in the mixed valent layer compound NaV2O5 is presented which provides a consistent description of exchange both in the disordered and charge ordered state. Starting from results of band structure calculations for NaV2O5 first an underlying electronic model for a ladder unit in the Trellis lattice is formulated. By using the molecular orbital representation for intra-rung electronic states a second-order perturbation procedure is developed and an effective spin-chain model for a ladder is derived. Variation of the resulting superexchange integral J is examined numerically as the ladder system evolves from a charge disordered to the extreme (’zig-zag’) charge ordered state. It is found that the effective intraladder superexchange is always antiferromagnetic. PACS. 71.10.Fd, 75.30.Et, 75.30.Mb Typeset using REVTEX 1
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0 Effective Charge and Spin Hamiltonian for the Quarter - Filled Ladder Compound α ′ - NaV 2 O 5
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