Supercurrent, Multiple Andreev Reflections and Shapiro Steps in InAs Nanosheet Josephson Junctions
Supercurrent, Multiple Andreev Reflections and Shapiro Steps in InAs Nanosheet Josephson Junctions
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DOI：
10.1021/acs.nanolett.3c01450
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发表时间：
2023-07-14
期刊：
影响因子：
10.8
通讯作者：
Xu，Hongqi
中科院分区：
文献类型：
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作者：
Yan，Shili;Su，Haitian;Xu，Hongqi
我们报道了由独立的InAs纳米片制成的平面约瑟夫森结器件中邻近感应超导电性的实验研究。采用分子束外延生长纳米片，将纳米片与超导体Al电极直接接触，制成约瑟夫森结器件。通过低温载流子输运测量，对所制备的器件进行了测试。测量结果表明，该器件具有栅极可调的超导电流、多次安德烈夫反射和良好的超导体-半导体界面。研究了约瑟夫森结在不同磁场和温度下的超导特性，并基于Bardeen-Cooper-Schrieffer(BCS)理论进行了分析。在不同功率和频率的微波辐射下，对交流约瑟夫森效应进行了测量，观察到了整数个夏皮罗阶跃。我们的工作表明，基于InAs纳米薄片的混合器件是研究物理前沿的理想系统，例如二维拓扑超导。
We report an experimental study of proximity induced superconductivity in planar Josephson junction devices made from free-standing InAs nanosheets. The nanosheets are grown by molecular beam epitaxy, and the Josephson junction devices are fabricated by directly contacting the nanosheets with superconductor Al electrodes. The fabricated devices are explored by low-temperature carrier transport measurements. The measurements show that the devices exhibit a gate-tunable supercurrent, multiple Andreev reflections, and a good quality superconductor-semiconductor interface. The superconducting characteristics of the Josephson junctions are investigated at different magnetic fields and temperatures and are analyzed based on the Bardeen–Cooper–Schrieffer (BCS) theory. The measurements of the ac Josephson effect are also conducted under microwave radiations with different radiation powers and frequencies, and integer Shapiro steps are observed. Our work demonstrates that InAs nanosheet based hybrid devices are desired systems for investigating the forefront of physics, such as two-dimensional topological superconductivity.