Avoided critical behavior in a uniformly frustrated system

Abstract

We study the effects of weak long-ranged antiferromagnetic interactions of strength Q on a spin model with predominant short-ranged ferromagnetic interactions. In three dimensions, this model exhibits an avoided critical point in the sense that the critical temperature T c ( Q = 0) is strictly greater than lim Q→0 T c ( Q). The behavior of this system at temperatures less than T c ( Q = 0) is controlled by the proximity to the avoided critical point. We also quantize the model in a novel way to study the interplay between charge-density wave and superconducting order.