Superexchange in the quarter- filled two- leg ladder system NaV2O5

Abstract

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 intra- ladder superexchange is always antiferromagnetic.

18 pages Revtex, 7 Postscript figures

References in corpus (2)

• Coexistence of charge density wave and spin-Peierls orders in quarter-filled quasi-one dimensional correlated electron systems
• Response: Spin-Singlet clusters in the ladder compound NaV2O5

Cited by in corpus (6)

• Temperature dependence of optical spectral weights in quarter-filled ladder systems
• Optical properties, electron-phonon coupling, and Raman scattering of vanadium ladder compounds
• A microscopic model for the structural transition and spin gap formation in alpha'-NaV2O5
• Charge order induced by electron-lattice interaction in NaV2O5
• Exact diagonalisation study of charge order in the quarter-filled two-leg ladder system NaV2O5
• Isospin model for suppression of charge order in hole- doped NaV_2O_5