Sliding mode and breaking of analyticity in the double-chain model of incommensurate composites

The double chain model (DCM) generalizes the Frenkel-Kontorova model for co mposite systems, coping with situations when both subsystems are deformable . We show how the shape and amplitude of the intermodulation of subsystems depend on the intersubsystem interaction potential, elastic constants, and average repeat distances of the subsystems. We characterize and study the b ehavior of the sliding mode, that is a pseudo-Goldstone mode of the system. DCM undergoes an analyticity breaking transition that leads to intrinsic p inning of the sliding mode, when the strength of the intersubsystem couplin g is increased above a threshold value. [S0163-1829(99)02042-1].