POINT-CONTACT STUDY OF FAST AND SLOW 2-LEVEL FLUCTUATORS IN METALLIC GLASSES

Distinct peaks in the differential resistance of point contacts of met allic glasses have been observed around zero bias. These peaks can be attributed to the interaction between conduction electrons and fast sw itching two-level fluctuators (TLF). Discrete jumps between two such p eaks were found to occur, which can be explained by a modulation of th e electron-TLF coupling by defects, present in the vicinity of the con tact, that slowly switch between two configurations.