Université Grenoble Alpes, CEA, INAC-Pheliqs , 38000 Grenoble , France.
Department of Physics and Astronomy , University of Pittsburgh , Pittsburgh , Pennsylvania 15260 , United States.
Nano Lett. 2019 Feb 13;19(2):1023-1027. doi: 10.1021/acs.nanolett.8b04275. Epub 2019 Jan 22.
Hybrid superconductor-semiconductor structures attract increasing attention owing to a variety of potential applications in quantum computing devices. They can serve the realization of topological superconducting systems as well as gate-tunable superconducting quantum bits. Here, we combine a SiGe/Ge/SiGe quantum-well heterostructure hosting high-mobility two-dimensional holes and aluminum superconducting leads to realize prototypical hybrid devices, such as Josephson field-effect transistors (JoFETs) and superconducting quantum interference devices (SQUIDs). We observe gate-controlled supercurrent transport with Ge channels as long as one micrometer and estimate the induced superconducting gap from tunnel spectroscopy measurements. Transmission electron microscopy reveals the diffusion of Ge into the Al contacts, whereas no Al is detected in the Ge channel.
混合超导体-半导体结构由于在量子计算设备中的各种潜在应用而引起越来越多的关注。它们可以用于实现拓扑超导系统以及栅控超导量子比特。在这里，我们结合了一个具有高迁移率二维空穴的 SiGe/Ge/SiGe 量子阱异质结构和铝超导引线，以实现原型混合器件，如约瑟夫森场效应晶体管（JoFET）和超导量子干涉器件（SQUID）。我们观察到具有 Ge 沟道的栅控超导电流传输，其长度可达一微米，并从隧道谱测量中估计出诱导超导能隙。透射电子显微镜显示 Ge 扩散到 Al 接触中，而在 Ge 沟道中没有检测到 Al。
