Metastability of commensurate and incommensurate structures in epitaxial films

Limits of stability for the range of metastable phases in two-dimensional epitaxial monolayers are calculated. The mean misfit between the monolayer and the substrate changes by addition or removal of solitons (or misfit dislocations) and metastability arises from the energy barrier for these processes. The behaviour is similar to that of a one-dimensional modulated chain of atoms with free ends.