Sine-Gordon theory of the non-Néel phase of two-dimensional quantum antiferromagnets.

Abstract

We examine a recently developed sine-Gordon model description of the non-N\'eel phase of quantum antiferromagnets on two-dimensional bipartite lattices. Using a spatial dimensionality d=1+\ensuremath{\epsilon} expansion we argue that the model always scales to its strong-coupling limit and displays spin Peierls or valence-bond-solid order. The structure of the theory in this strong-coupling limit bears a remarkable resemblance to a fermionic large-N limit of the nearest-neighbor SU(N) antiferromagnet.