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  Superconductivity and strong correlations in graphene quantum devices


Daniel Rodan-Legrain (Massachussetts Institute of Technology)


Date/Horaire : le mardi 26 mars 2024 à 14:00


Lieu : Salle Rémy Lemaire K223, Institut Néel


Résumé : Graphene possesses exceptional properties that, since its discovery, have attracted wide attention from the scientific and engineering communities. In this talk, I will present a series of experiments via two different approaches, i.e., proximity effect and twist angle design, to induce superconductivity and strong correlations in graphene-based systems—two phenomena that do not intrinsically occur in this material. In the first part of my talk, graphene is flanked by two superconductors and inherits their superconducting properties by proximity effect. A superconductor-graphene-superconductor junction is coupled to a superconducting circuit to create and manipulate the first graphene-based transmon qubit. In the second part of my talk, the electronic properties of graphene-based systems are engineered by controlling the relative twist angle between the atomic planes. In particular, when two graphene sheets are stacked on top of each other near the “magic angle” ≈ 1.1°, nearly flat bands develop, featuring superconductivity and correlated insulating states. I will show that local electrostatic control over the different electronic phases of magic-angle twisted bilayer graphene (MATBG) enables the creation of versatile hyper-tunable quantum devices. I will also present transport, local electronic compressibility, and nano-optics experiments to demonstrate the emergence of exotic electronic phases in MATBG. Last, I will discuss studies of novel 2D moiré systems beyond MATBG.