The effect of quantum fluctuations on the ferromagnetic-helix transition in a Heisenberg tetragonal lattice with competing in-plane interactions

A. B. Harris, Alberto Pimpinelli, E. Rastelli, A. Tassi

Research output: Contribution to journalArticle

6 Scopus citations

Abstract

Perturbative treatments of quantum fluctuations in Heisenberg helimagnets starting from the classical approximation fail because for S to infinity the spin wave is well defined only for a fixed helix wavevector Q. Recently an exact T-matrix evaluation of the contribution to the ground-state energy from long-wavelength quantum fluctuations near the classical ferromagnetic-helix (F-H) transition line was performed in order to discuss the zero-temperature phase diagram in the j2-J3 plane, where j2 (j3) sets the scale of second (third) neighbour interactions in the basal plane. For the hexagonal lattice it was shown that quantum fluctuations could change from second to first order the F-H transition near the F-AF-H classical triple point, where AF denotes antiferromagnet. Here the authors give analogous calculations on a tetragonal lattice, which show unexpected lattice-dependent features. In addition to a behaviour similar to that found on the hexagonal lattice near the F-AF-H triple point, the change of the order of transition is found also on a semi-infinite part of the classical F-H phase boundary.

Original languageEnglish (US)
Article number005
Pages (from-to)3821-3831
Number of pages11
JournalJournal of Physics: Condensed Matter
Volume1
Issue number24
DOIs
StatePublished - Dec 1 1989

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics

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