Fully tunable Magic Angle Twisted Bilayer Graphene Josephson Junction

Superconductivity and correlated insulating states have recently been observed in ‘magic-angle’ twisted bilayer graphene (MATBG) heterostructures at twist angles close to 1.1 degrees, featuring nearly-flat bands owing to strong interlayer coupling. MATBG offers a new playground to study superconductivity and strongly correlated physics with an unprecedented degree of tunability. One of the elemental superconducting devices are Josephson Junctions, where two superconductors are coupled by a non-superconducting weak link. In this work, we exploit such tunability to create a fully tunable 2D Josephson Junction allowing to independently control the electronic state of the weak link and the rest of the junction via multiple electrostatic gates. The MATBG electrodes can thus be brought into a superconducting state, either in the hole regime or the electron regime, while the narrow junction at the center of the device can be tuned into any possible state of the phase diagram of MATBG (from metal, band insulator, charge neutrality, correlated insulator, superconductor). Such devices may pave the way towards new geometries in the study of strongly correlated systems, tunable superconducting qubits, and fully-integrated 2-dimensional electronics for the future nanodevice technology.