Orderly disorder in magic-angle twisted trilayer graphene
Simon Turkel, Joshua Swann, Ziyan Zhu, Maine Christos, Kenji Watanabe, Takashi Taniguchi, Subir Sachdev, Mathias S. Scheurer, Efthimios Kaxiras, Cory R. Dean, Abhay N. Pasupathy
Abstract
Magic-angle twisted trilayer graphene (TTG) has recently emerged as a platform to engineer strongly correlated flat bands. We reveal the normal-state structural and electronic properties of TTG using low-temperature scanning tunneling microscopy at twist angles for which superconductivity has been observed. Real trilayer samples undergo a strong reconstruction of the moiré lattice, which locks layers into near-magic-angle, mirror symmetric domains comparable in size with the superconducting coherence length. This relaxation introduces an array of localized twist-angle faults, termed twistons and moiré solitons, whose electronic structure deviates strongly from the background regions, leading to a doping-dependent, spatially granular electronic landscape. The Fermi-level density of states is maximally uniform at dopings for which superconductivity has been observed in transport measurements.