Systematic analysis of superconductivity in magic-angle twister bilayer graphene nanodevices*

Superconductivity and correlated insulating states have recently been observed in ‘magic-angle’ twisted bilayer graphene heterostructures at twist angles close to 1.1 degrees, featuring nearly-flat bands owing to strong interlayer coupling. We here perform a systematic study of superconductivity and correlated phenomena in more than 10 different superconducting devices with angles comprised between 0.99 degrees and 1.19 degrees. Angle dependence of critical temperature and field, together with the interplay between superconductivity and insulating states, are examined. Higher quality devices allow us to extend the analysis to superconductivity when doping the twisted bilayer system with electrons. This 2D superconductor, based on graphene moiré superlattices, offers a uniquely tunable, clean and relatively simple platform for the investigation of strongly correlated physics.