The antiferromagnetic spin 1/2 chain with competing dimers and plaquettes: Numerical versus exact results

J. Richter; N. B. Ivanov; J. Schulenburg

doi:10.1088/0953-8984/10/16/015

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The antiferromagnetic spin 1/2 chain with competing dimers and plaquettes: Numerical versus exact results

J. Richter·N. B. Ivanov·J. Schulenburg

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Abstract

We examine the ground state and the excitations of an one-dimensional Heisenberg spin 1/2 antiferromagnet with alternating dimers and four-spin plaquettes (dimer-plaquette chain). The properties of the system depend on the competing dimer and plaquette bonds. Several exact, exact-numerical and perturbational results are presented. We find that the system is gapped for all parameter values. For the latter one we find an effective S=1 Haldane like behaviour in the limit of dominating dimer bonds. The model considered is related to the recently found 1/5-depleted square-lattice Heisenberg system $CaV_4O_9$.

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J. Richter, N. B. Ivanov, J. Schulenburg. 1998-02-13. The antiferromagnetic spin 1/2 chain with competing dimers and plaquettes: Numerical versus exact results. https://doi.org/10.1088/0953-8984%2F10%2F16%2F015

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