Phenomenological approach to a transition into the incommensurate phase for thin films

TL;DR

This paper develops a phenomenological theory for incommensurate phase transitions in thin films with a single-component order parameter, analyzing how film size influences transition temperature.

Contribution

It introduces a model for incommensurate phase transition in thin films considering a slowly-varying amplitude of the order parameter.

Findings

Size effects lower the transition temperature in thin films.

The order parameter distribution varies smoothly across the film.

The theory applies to single-component order parameters in incommensurate phases.

Abstract

A phenomenological theory of the incommensurate phase transition in thin films is presented for the case of the single-component order parameter. The order parameter distribution over the film is obtained under the assumption of slowly-varying amplitude. The size effect on the temperature of the phase transition into the incommensurate phase has been considered.