Field theories for frustrated antiferromagnetic spin chains

Rao, S and Sen, D (1997) Field theories for frustrated antiferromagnetic spin chains. In: Journal Of Physics-Condensed Matter, 9 (8). pp. 1831-1839.

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Abstract

We study the antiferromagnetic spin chain with both dimerization and frustration. The classical ground state has three phases, a Neel phase, a spiral phase and a collinear phase, which we study through a nonlinear sigma-model approach. In the spiral phase, the held theory becomes SO(3) x SO(3) and Lorentz invariant at long distances, a model which is exactly solvable. The low-energy spectrum is doubly degenerate with massive 'elementary' spin-1/2 particles and 'two-particle' triplet and singlet physical excitations. The field theory also supports Z(2) solitons which lead to a double degeneracy of the ground state for half-integer spins (when there is no dimerization).

Item Type:	Journal Article
Publication:	Journal Of Physics-Condensed Matter
Publisher:	Institute of Physics
Additional Information:	Copyright of this article belongs to Institute of Physics.
Department/Centre:	Division of Physical & Mathematical Sciences > Centre for Theoretical Studies (Ceased to exist at the end of 2003)
Date Deposited:	21 Jul 2009 10:48
Last Modified:	19 Sep 2010 05:26
URI:	http://eprints.iisc.ac.in/id/eprint/18995

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