Plasmon Clues Hint at Unconventional Pairing in Magic-Angle Graphene
Barrier and colleagues stacked two decoupled twisted bilayer graphene layers and used independent gating to screen electrons in the superconducting, magic-angle layer. They observed that stronger interlayer screening suppresses superconductivity, a result opposite to expectations for conventional, phonon-mediated pairing and consistent with an unconventional mechanism—possibly plasmon-mediated—driven by the high density of states in the flat moiré bands and electronic correlations. The findings challenge phonon-dominated explanations and may relate to the disappearance of correlated insulating phases, signaling a new direction for understanding superconductivity in graphene-based systems.
