Lifting of multiphase degeneracy by quantum fluctuations.

  title={Lifting of multiphase degeneracy by quantum fluctuations.},
  author={Harris and Micheletti and Yeomans},
  journal={Physical review. B, Condensed matter},
  volume={52 9},
We study the effect of quantum fluctuations on the multiphase point of the Heisenberg model with first- and second-neighbor competing interactions and strong uniaxial spin anisotropy $D$. By studying the structure of perturbation theory we show that the multiphase degeneracy which exists for $S=\infty$ (i.e., for the ANNNI model) is lifted and that the effect of quantum fluctuations is to stabilize a sequence of phases of wavelength 4,6,8,...~. This sequence is probably an infinite one. We also… 
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