Incommensurate-Commensurate Crossover in Generalized One-Dimensional Ginzburg-Landau Fields

Abstract
Effects of the commensurability energy on the fluctuating incommensurate state in one-dimensional systems are investigated exactly by means of the transfer integral method on the basis of the generalized Ginzburg-Landau model. At low temperatures the fundamental eigenvalue equation of the method is solved by expanding it in powers of the temperature in analogy with the ordinary WKB method. Our analytic results on the low temperature behavior of the correlation length can be interpreted in terms of phasons and discommensurations. At intermediate temperatures various physical quantities are calculated numerically. In particular from the temperature dependence of the correlation length we determine the crossover point from the fluctuating incommensurate state to the commensurate state.