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Magnetic-field-induced parity effect in insulating Josephson junction chains

Thu 15Nov2018

From 17:00

At National University of Science and Technology MISIS

Superconducting Metamaterials Laboratory / smm@misis.ru


Schmidt seminar on superconductivity


The seminar “Magnetic-field-induced parity effect in insulating Josephson junction chains” in the frame of  Schmidt seminar on superconductivity will be held in the National University of Science and Technology MISIS (Moscow, Leninsky prospect, 4) lecture hall № Б-607 (6th floor), on 15th of November 2018 at 17:00 by Prof. Timothy Duty, Lab SC2, School of Physics, Faculty of Science, University of New South Wales, Australia.


Magnetic-field-induced parity effect in insulating Josephson junction chains 

Tim Duty, Karin Cedergren, Sergey Kafanov, Roger Ackroyd and Jared H. Cole 

We report the experimental manifestation of even-odd parity effects in the transport characteristics of insulating Josephson junction chains, which occur as the superconducting gap is suppressed by applied magnetic fields at millikelvin temperatures. The primary signature is a non-monotonic dependence of the critical voltage, Vc, for the onset of charge transport through the chain, with the parity crossover indicated by a maximum of Vc at the parity field B*, We also observe a distinctive change in the transport characteristics across the parity transition, indicative of Cooper-pair dominated transport below B*, giving way to single-electron dominated transport above B*, For fields applied in the plane of the superconducting aluminum films, the parity effect is found to occur at the field, B*||, such that the superconducting gap equals the single-electron charging energy, Δ(B*||)=EC. On the contrary, the parity effect for perpendicularly applied fields can occur at relatively lower fields, B*⊥≃ 2Φ0/AI, depending only on island area, AI. In this case, the parity effect occurs in sync with formation of the single-vortex state of the islands in the chain. Our results suggest a novel explanation for the insulating peak observed in disordered superconducting films and one-dimensional strips patterned from such films, which occurs at a finite magnetic field.

Language: English

Everyone is welcome!