Spectroscopic Signatures of Strong Correlations and Unconventional Superconductivity in Twisted Trilayer Graphene – Part 1

Among the moire material family, magic-angle twisted bilayer and trilayer graphene have shown robust superconductivity. However, the microscopic mechanisms leading to superconductivity in these systems are still elusive. We utilized scanning tunneling microscopy to study correlated phases and superconductivity in twisted trilayer graphene. After establishing correlation effects on the band structure such as flavor polarizing phase transitions and doping-dependent band deformations, we identified superconducting gaps around the half-filling for hole doping by observing pronounced coherence peaks that disappear at around the reported critical temperatures and fields. Moreover, the gap survives well above the critical temperatures and fields, reminiscent of pseudogap phase in other unconventional superconductors. Our results highlight the unconventional nature of superconductivity in magic angle twisted trilayer graphene.