Group theory and octupolar order in URu 2Si 2

Annamária Kiss, P. Fazekas

Research output: Contribution to journalArticle

88 Citations (Scopus)

Abstract

Recent experiments on URu 2Si 2 show that the low-pressure hidden order is nonmagnetic but it breaks time reversal invariance. Restricting our attention to local order parameters of 5f 2 shells, we find that the best candidate for hidden order is staggered order of either T zβ or T xyz octupoles. Group theoretical arguments for the effect of symmetry-lowering perturbations (magnetic field, mechanical stress) predict behavior in good overall agreement with observations. We illustrate our general arguments on the example of a five-state crystal field model which differs in several details from models discussed in the literature. The general appearance of the mean field phase diagram agrees with the experimental results. In particular, we find that (a) at zero magnetic field, there is a first-order phase boundary between octupolar order and large-moment antiferromagnetism with increasing hydrostatic pressure; (b) arbitrarily weak uniaxial pressure induces staggered magnetic moments in the octupolar phase; and (c) a new phase with different symmetry appears at large magnetic fields.

Original languageEnglish
Article number054415
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume71
Issue number5
DOIs
Publication statusPublished - Feb 2005

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Group theory
group theory
Magnetic fields
magnetic fields
Antiferromagnetism
antiferromagnetism
symmetry
Phase boundaries
Hydrostatic pressure
Invariance
Magnetic moments
hydrostatic pressure
Phase diagrams
crystal field theory
invariance
low pressure
magnetic moments
phase diagrams
moments
perturbation

ASJC Scopus subject areas

  • Condensed Matter Physics

Cite this

Group theory and octupolar order in URu 2Si 2 . / Kiss, Annamária; Fazekas, P.

In: Physical Review B - Condensed Matter and Materials Physics, Vol. 71, No. 5, 054415, 02.2005.

Research output: Contribution to journalArticle

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