Renormalization-group approach to commensurate-incommensurate transitions in two dimensions

Abstract

We present a renormalization-group-approach analysis of the commensurate-incommensurate transition of the two-dimensional classical sine-Gordon system which includes incommensurability as a new renormalizable parameter. The critical behavior of various quantities shows corrections with respect to the simpler self-consistent harmonic approximation (SCHA). However, our result for the phase boundary still has a SCHA-type $T$ dependence, suggesting that incommensurability tends to suppress the role of fluctuations.