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Meta-Plaquette Expansion for the Triplet Excitation Spectrum in CaV$_4$O$_9$

Zheng Weihong·J. Oitmaa·C. J. Hamer
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Abstract

We study antiferromagnetic, $S=1/2$ Heisenberg models with nearest and second neighbor interactions on the one-fifth depleted square lattice which describes the spin degrees of freedom in the spin-gap system CaV$_4$O$_9$. The meta-plaquette expansion for the triplet excitation spectrum is extended to fifth order, and the results are compared with experimental data on CaV$_4$O$_9$. We attempt to locate the phase boundary between magnetically ordered and gapped phases.

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Zheng Weihong, J. Oitmaa, C. J. Hamer. 1998-07-17. Meta-Plaquette Expansion for the Triplet Excitation Spectrum in CaV$_4$O$_9$. https://doi.org/10.1103/physrevb.58.14147

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