When near a magic twist angle, bilayer graphene transforms from a weakly correlated Fermi-liquid to a strongly correlated two-dimensional electron system with electronic properties that are extremely sensitive to its carrier density. Magic-angle twisted bilayer graphene (MATBG) has been demonstrated to host a range of exotic physi-cal properties, such as unconventional superconductivity, correlated insulating states, magnetism, and quantized anomalous Hall states. The goal of the project is to explore the extraordinary properties of MATBG when inte-grated into a multilayer gated geometry, with a particular focus on the interplay between the super-lattice band and the electronic confinement. We exploit this unprecedented tunability to create an all-in-one device that can be used for both superconducting electronics and normal-state operations, bridging the fields of strongly corre-lated systems and single-electron tunneling devices.

Collaborators in laboratory: Michael Stiefel, Prof. Michel Calame

External partners: Prof. Hai Hu (National Center for Nanoscience and Technology, China)

Funding: Empa internal research call

MATBG and multi-layer gate device

1. Y. Cao et al., "Unconventional superconductivity in magic-angle graphene superlattices." Nature 556, 43-50 (2018).
2. Y. Cao et al., "Correlated insulator behaviour at half-filling in magic-angle graphene superlattices." Na-ture 556, 80-84 (2018).
3. D. Rodan-Legrain et al., "Highly tunable junctions and non-local Josephson effect in magic-angle gra-phene tunnelling devices." Nature Nanotechnology 16, 769-775 (2021).
4. F. K. de Vries et al., "Gate-defined Josephson junctions in magic-angle twisted bilayer graphene." Na-ture Nanotechnology 16, 760-763 (2021).