PHONON-ASSISTED RESISTANCE JUMPS OF A MESOSCOPIC WIRE

In recent experiments, the resistance of a thin Bi wire was shown to b e strongly influenced by a single bistable defect, whose jump rate wel l below 1 K could be explained by the interaction with conduction elec trons. We study the defect dynamics arising from coupling to both cond uction electrons and phonons. The resulting rate shows a minimum at th e temperature where multi-phonon processes become important aml increa ses exponentially above it. Inserting known values for the material pa rameters of the host, our result provides a good fit to the data obser ved between 0.1 and 2 K, and assesses the relevance of phonon-assisted hopping above 1 K. (C) 1997 Elsevier Science B.V.