TOPOLOGICAL DEFECTS, MULTIPARTICLE EXCHANGE AND REENTRANT MELTING

Coherent quantum-mechanical climb motion of a dislocation pair involve s exchanges of an array of particles. For electrons in a magnetic fiel d this motion becomes possible near odd denominator filling factors, t he pair is liberated and its energy is decreased, consistent with the lowering of the activation energy in recent transport measurements by Jiang et al. This decrease also provides a mechanism of re-entrant mel ting via spontaneous generation of dislocation pairs.