Splitting of commensurate-incommensurate phase transition

Abstract

The discrete nature of a lattice is shown to manifest itself in a splitting of the commensurate-incommensurate (C-I) phase transition into two phase transitions. The first of them brings an overlayer to a state with a pinned soliton superstructure. The second phase transition unpins the soliton superstructure supplying it with a continuous degree of freedom. The treatment by Aubry [1] is rederived to simplify its mathematical formulation