Spin-S bilayer Heisenberg models: Mean-field arguments and numerical calculations

Martin P. Gelfand; Zheng Weihong; C. J. Hamer; J. Oitmaa

doi:10.1103/physrevb.57.392

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Spin-S bilayer Heisenberg models: Mean-field arguments and numerical calculations

Martin P. Gelfand·Zheng Weihong·C. J. Hamer·J. Oitmaa

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Abstract

Spin-S bilayer Heisenberg models (nearest-neighbor square lattice antiferromagnets in each layer, with antiferromagnetic interlayer couplings) are treated using dimer mean-field theory for general S and high-order expansions about the dimer limit for S=1, 3/2,...,4. We suggest that the transition between the dimer phase at weak intraplane coupling and the Neel phase at strong intraplane coupling is continuous for all S, contrary to a recent suggestion based on Schwinger boson mean-field theory. We also present results for S=1 layers based on expansions about the Ising limit: In every respect the S=1 bilayers appear to behave like S=1/2 bilayers, further supporting our picture for the nature of the order-disorder phase transition.

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Martin P. Gelfand, Zheng Weihong, C. J. Hamer, J. Oitmaa. 1997-05-20. Spin-S bilayer Heisenberg models: Mean-field arguments and numerical calculations. https://doi.org/10.1103/physrevb.57.392

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