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Temperature behavior of the magnon modes of the square lattice antiferromagnet

A. Sherman·M. Schreiber
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Abstract

A spin-wave theory of short-range order in the square lattice Heisenberg antiferromagnet is formulated. With growing temperature from T=0 a gapless mode is shown to arise simultaneously with opening a gap in the conventional spin-wave mode. The spectral intensity is redistributed from the latter mode to the former. For low temperatures the theory reproduces results of the modified spin-wave theory by M.Takahashi, J.E.Hirsch et al. and without fitting parameters gives values of observables in good agreement with Monte Carlo results in the temperature range 0 <= T < 0.8J where J is the exchange constant.

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A. Sherman, M. Schreiber. 1999-05-24. Temperature behavior of the magnon modes of the square lattice antiferromagnet. https://doi.org/10.1103/physrevb.60.10180

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