Resonant tunneling in small current-biased Josephson Junctions
- Univ. of California, Berkeley, CA (United States)
Effects of resonant tunneling between bound quantum states of a current-biased Josephson tunnel junction is studied both theoretically and experimentally. Several effects are predicted to arise from resonant tunneling, including a series of voltage peaks along the supercurrent branch of the current-voltage characteristic, and enhanced rate of escape from zero voltage state to voltage state at particular values of bias current. A model is developed to estimate magnitude and duration of voltage peaks, and to estimate enhancement of the escape rate, which appears as peaks in the rate as a function of bias current. An experimental investigation was carried out in an attempt to observe these predicted peaks in the escape rate distribution in a current-biased DC SQUID, which is shown to be dynamically equivalent to a Josephson junction with adjustable critical current. Electrical contact to each SQUID (fabricated from aluminium) was made through high resistance thin film leads located on the substrate. These resistors provided a high impedance at the plasma frequency which is for the isolation of the SQUID from its electromagnetic environment. Measurements were carried out on a dilution refrigerator at temperatures as low as 19 mK. No evidence was found for resonant tunneling; this is attributed to effective temperatures of hundreds of millikelvin. The behavior is well explained by a heating model where the high effective temperatures are generated by ohmic heating of the electron gas of the isolation resistors, which decouples from the phonon system (hot electron effect). The prospects for further theoretical and experimental research are discussed.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 10174446
- Report Number(s):
- LBL--35671; ON: DE94016875
- Country of Publication:
- United States
- Language:
- English
Similar Records
Resonant tunneling in small current-biased Josephson junctions
Effect of dissipation on macroscopic quantum tunneling
Macroscopic quantum tunneling and energy-level quantization in the zero voltage state of the current-biased Josephson junction
Journal Article
·
Mon Dec 31 23:00:00 EST 1990
· Physical Review, B: Condensed Matter; (USA)
·
OSTI ID:6096652
Effect of dissipation on macroscopic quantum tunneling
Conference
·
Sat Feb 28 19:00:00 EST 1987
·
OSTI ID:6000066
Macroscopic quantum tunneling and energy-level quantization in the zero voltage state of the current-biased Josephson junction
Thesis/Dissertation
·
Mon Dec 31 19:00:00 EST 1984
·
OSTI ID:6854992