Spin gap in chains with hidden symmetries

M. N. Kiselev, D. N. Aristov, K. Kikoin

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16 Scopus citations

Abstract

We investigate the formation of a spin gap in one-dimensional models characterized by groups with hidden dynamical symmetries. A family of two-parametric models of isotropic and anisotropic spin-rotator chains (SRC's) characterized by SU(2)×SU(2) and SO(2)×SO(2)×Z 2×Z 2 symmetries is introduced to describe the transition from SU(2) to SO(4) antiferromagnetic Heisenberg chains. The excitation spectrum is studied with the use of the Jordan-Wigner transformation generalized for o 4 algebra and by means of the bosonization approach. Hidden discrete symmetries associated with invariance under various particle-hole transformations are discussed. We show that the spin gap in SRC Hamiltonians is characterized by the scaling dimension 2/3, in contrast to dimension 1 in the conventional Haldane problem.

Original languageEnglish
Article number092404
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume71
Issue number9
DOIs
StatePublished - 1 Mar 2005

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