Dislocations and the Commensurate-Incommensurate Transition in Two Dimensions

Abstract

The incommensurate adsorbed solid is found to become unstable to dislocations when the lattice period approaches that of a sufficiently low-order commensurate phase such as a 2\ifmmode\times\else\texttimes\fi{}1 rectangular overlayer or the $(\sqrt{3}\ifmmode\times\else\texttimes\fi{}\sqrt{3})R30\ifmmode^\circ\else\textdegree\fi{}$ hexagonal structure which occurs for krypton on graphite. In these cases, a fluid phase is expected between the commensurate and incommensurate solids.