Phase Transitions of Two-Dimensional Helical XY Models

Abstract

A study is made on a two-dimensional classical XY model with anisotropic coupling yielding a helical ground state. Two phase transition temperatures are estimated in the neighborhood of the Lifshitz point by examining the stability of the helimagnetic phase against formation of vortices and domain walls between regions of opposing chirality of the helical state. These temperatures are different from those obtained by Garel and Doniach.