Crossover from Josephson Effect to Single Interface Andreev Reflection in Asymmetric Superconductor/Nanowire Junctions
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- 作者：H. Y. G眉nel ; N. Borgwardt ; I. E. Batov ; H. Hardtdegen ; K. Sladek ; G. Panaitov ; D. Gr眉tzmacher ; Th. Sch盲pers
- 刊名：Nano Letters
- 出版年：2014
- 出版时间：September 10, 2014
- 年：2014
- 卷：14
- 期：9
- 页码：4977-4981
- 全文大小：293K
- ISSN：1530-6992
文摘
We report on the fabrication and characterization of symmetric nanowire-based Josephson junctions, that is, Al- and Nb-based junctions, and asymmetric junctions employing superconducting Al and Nb. In the symmetric junctions, a clear and pronounced Josephson supercurrent is observed. These samples also show clear signatures of subharmonic gap structures. At zero magnetic field, a Josephson coupling is found for the asymmetric Al/InAs-nanowire/Nb junctions as well. By applying a magnetic field above the critical field of Al or by raising the temperature above the critical temperature of Al the junction can be switched to an effective single-interface superconductor/nanowire structure. In this regime, a pronounced zero-bias conductance peak due to reflectionless tunneling has been observed.