Dynamics of dislocation-mediated melting in a two-dimensional lattice in the presence of an oscillatory applied strain.

Abstract

The temperature and frequency dependence of the power dissipated in a two-dimensional crystal subjected to an applied strain is shown to exhibit a distinct signature for dislocation-dissociation melting. The power absorption is analogous to the case of thin helium films subjected to an applied velocity field. Power loss by dislocation motion in the compressional mode is severely limited by the presence of nonequilibrium densities of interstitial and vacancy defects that are created or annihilated by dislocation climb. Tables of analogs between dislocations, vortices, and charges in two-dimensional systems are presented. The relation of the results to published experiments is discussed.