Germanium Quantum-Well Josephson Field-Effect Transistors and Interferometers
Florian Vigneau (Université Grenoble Alpes)
Raisei Mizokuchi (Université Grenoble Alpes)
Dante Colao Zanuz (Université Grenoble Alpes)
Xuhai Huang (University of Pittsburgh)
Susheng Tan (University of Pittsburgh)
Romain Maurand (Université Grenoble Alpes)
Sergey Frolov (University of Pittsburgh)
Amir Sammak (Kavli institute of nanoscience Delft, TU Delft - Business Development)
Giordano Scappucci (TU Delft - QCD/Scappucci Lab, Kavli institute of nanoscience Delft)
Francois Lefloch (Université Grenoble Alpes)
Silvano De Franceschi (Université Grenoble Alpes)
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Abstract
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.