Gate-defined superconducting channel in magic-angle twisted bilayer graphene

Abstract

Magic-angle twisted bilayer graphene (MATBG) combines in one single material different phases like insulating, metallic and superconducting. These phases and their in-situ tunability make MATBG an important platform for the fabrication of superconducting devices. We realize a split gate-defined geometry which enables us to tune the width of a superconducting channel formed in MATBG. We observe a smooth transition from superconductivity to highly resistive transport by progressively reducing the channel width using the split gates or by reducing the density in the channel. Using the gate-defined constriction, we control the flow of the supercurrent, either guiding it through the constriction or throughout the whole device or even blocking its passage completely. This serves as a foundation for developing quantum constriction devices like superconducting quantum point contacts, quantum dots, and Cooper-pair boxes in MATBG.

arXiv comment7 pages, 5 figures

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Cited by in corpus (4)

• Review of the tight-binding method applicable to the properties of moiré superlattices
• Gate-defined single-electron transistors in twisted bilayer graphene
• Topological phases, van Hove singularities, and spin texture in magic-angle twisted bilayer graphene in the presence of proximity-induced spin-orbit couplings
• Graphene Josephson Junctions for Engineering Motional Quanta