Dresden 2017 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 48: Superconductivity: Tunnelling, Josephson Junctions, SQUIDs 2

TT 48.2: Vortrag

Mittwoch, 22. März 2017, 15:15–15:30, HSZ 201

Superconducting nanowire loop capacitively coupled to a microwave resonator — •Hannes Rotzinger¹, Sebastian T. Skacel¹, Jochen Braumüller¹, Andre Schneider¹, Hans Mooij², and Alexey V. Ustinov¹ — ¹Karlsruher Institut für Technologie, Karlsruhe, Deutschland — ²Kavli Institute of NanoScience, Delft, the Netherlands

We present continuous and pulsed microwave measurements of a high-impedance superconducting loop with an embedded superconducting nanowire of 20 nm width and 250 nm length. In the experiment, we monitor the dispersive shift of a microwave resonator which couples capacitively to the loop. When applying weak magnetic fields, the system shows pronounced anti-crossings at the resonator frequency that occur at stable and reproducible fields. At larger fields, the anti-crossings are shifted hysteretically by magnetic flux values comparable to the magnetic flux quantum per loop area. We analyse the anti-crossings by two-tone measurements and find signatures of several specific two-level states at different magnetic fields. Rabi oscillations as well as T1 and T2 coherence times are measured by applying microwave pulses.