Fabrication and measurements of hybrid Nb/Al Josephson junctions and flux qubits with pi-shifters
| Autor: | Vladimir Ryazanov, Anastasia V. Shcherbakova, V. A. Oboznov, Vladislav O. Shkolnikov, Detlef Beckmann, Vitaly V. Bolginov, Alexey V. Ustinov, Michael J. Wolf, S. V. Egorov, K. V. Shulga, Kirill G. Fedorov |
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| Jazyk: | angličtina |
| Rok vydání: | 2014 |
| Předmět: |
Superconductivity
Shadow mask Josephson effect Flux qubit Quantum Physics Fabrication Materials science business.industry Condensed Matter - Superconductivity Metals and Alloys FOS: Physical sciences Condensed Matter Physics Magnetic field Superconductivity (cond-mat.supr-con) Qubit Condensed Matter::Superconductivity Materials Chemistry Ceramics and Composites Optoelectronics Electrical and Electronic Engineering business Quantum Physics (quant-ph) Electronic circuit |
| Popis: | We describe fabrication and testing of composite flux qubits combining Nb- and Al-based superconducting circuit technology. This hybrid approach to making qubits allows for employing pi-phase shifters fabricated using well-established Nb-based technology of superconductor-ferromagnet-superconductor Josephson junctions. The important feature here is to obtain high interface transparency between Nb and Al layers without degrading sub-micron shadow mask. We achieve this by in-situ Ar etching using e-beam gun. Shadow-evaporated Al/AlOx/Al Josephson junctions with Nb bias pads show the expected current-voltage characteristics with reproducible critical currents. Using this technique, we fabricated composite Nb/Al flux qubits with Nb/CuNi/Nb pi-shifters and measured their magnetic field response. The observed offset between the field responses of the qubits with and without pi-junction is attributed to the pi phase shift. The reported approach can be used for implementing a variety of hybrid Nb/Al superconducting quantum circuits. 9 pages, 5 figures |
| Databáze: | OpenAIRE |
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