Nature of the superconducting pairing in magic-angle twisted bilayer graphene

Determine the superconducting order-parameter symmetry and structure in twisted bilayer graphene near the magic angle, distinguishing among proposed candidates such as chiral d+id, chiral p+ip, or a coexistence of both, in order to clarify the nature of the unconventional superconductivity observed in this system.

Background

Twisted bilayer graphene (tBLG) exhibits unconventional superconductivity near the magic angle and has become a central platform for studying correlated and topological phases in moiré materials. Despite extensive theoretical proposals for various pairing symmetries, including p-, d-, and g-wave states, and several studies indicating potential chiral order, a definitive identification of the superconducting pairing symmetry in tBLG remains unsettled.

In this work, the authors analyze chiral p+ip superconductivity as a model pairing in tBLG and tDBLG to explore the resulting topological phases and Chern numbers. However, they explicitly note that the actual pairing symmetry in tBLG is still unclear, highlighting the need for experimental and theoretical resolution of the superconducting order parameter, which is critical for engineering and understanding topological superconductivity in twisted graphene systems.