Commensurate-Incommensurate Transitions with Quenched Random Impurities

Abstract

Commensurate-incommensurate transitions in uniaxial two-dimensional systems are examined in the presence of impurities that interact with domain walls. Exact Bethe-Ansatz calculations, tested by numerical studies, indicate that randomness is relevant and leads to new critical behavior—a discontinuity in the specific heat and divergence of domain size with an exponent of 1. The results are interpreted in terms of the behavior of a single interface. Global phase diagrams are presented and experimental implications are discussed.