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Tunable φ Josephson junction ratchet
R Menditto1, H Sickinger1, M Weides2
1Physikalisches Institut and Center for Quantum Science in LISA+, Universität Tübingen, Auf der Morgenstelle 14, D-72076 Tübingen, Germany.
Physical Review. E
|November 15, 2016
Summary
We show a Josephson ratchet that can operate against a counterforce, generating usable power. This tunable asymmetry device, based on a Josephson junction, demonstrates potential for energy harvesting applications.
Area of Science:
- Quantum electronics
- Condensed matter physics
Background:
- Josephson junctions are key components in quantum electronic devices.
- Understanding ratchet mechanics is crucial for energy harvesting and directed transport.
Purpose of the Study:
- To experimentally demonstrate a deterministic Josephson ratchet with tunable asymmetry.
- To investigate the ratchet's operation under an opposing DC current.
- To estimate the efficiency of the Josephson junction ratchet.
Main Methods:
- Fabrication and operation of a $\phi$ Josephson junction with a ferromagnetic barrier.
- Utilizing the underdamped regime for ratchet dynamics.
- Applying an external DC current as a counterforce.
Main Results:
- The Josephson ratchet operates deterministically with tunable asymmetry.
- The ratchet successfully functions against an applied counterforce, producing net output power.
- The efficiency of the $\phi$ Josephson junction ratchet was estimated.
Conclusions:
- The demonstrated Josephson ratchet offers a controllable system for directed transport.
- The ability to generate power against a counterforce highlights potential applications in quantum energy harvesting.
- Further research can optimize the efficiency and explore other configurations of Josephson ratchets.
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