LOW-TEMPERATURE BEHAVIOR OF A PHASE-SLIP CENTER

The differential resistance of the voltage-current characteristic generated by an isolated phase-slip center in a superconducting tin whisker has been measured down to 50 mK below its critical temperature. As a function of the temperature the differential resistance shows a resonancelike behavior with a maximum at the temperature where charge-imbalance waves excited by the phase-slip center have their maximum decay length, suggesting that the observed maximum of the differential resistance gives experimental evidence for charge-imbalance waves arising from a phase-slip center.