Abstract
Short metallic weak links of Nb are used for millimeter-wave mixer experiments at 100-110 GHz. When the weak links are connected to a voltage bias circuit with zero output impedance, subharmonic gap structures are observed as a large dynamic resistance region or a negative differential resistance region at voltages V/sub u/=2/spl Delta//ne on the I-V curve, where n=1, 2, 3, ... . These strong structures are caused by a resonance effect between the energy gap and the multiple Andreev reflections that are present whenever there is a spatial inhomogeneity of the pair potential. Enhancement of IF signal peaks is observed at the subgap voltages. These experimental results suggest the appearance of the density of states predicted theoretically by R. Kummel et al. The subharmonic gap structure and details of the SNS mixer experiment will be described.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
