Orderly disorder in magic-angle twisted trilayer graphene

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 moire 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 moire 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.

Automated summary

The magic-angle twisted trilayer graphene has shown a potential for engineering strongly correlated flat bands. Using low-temperature scanning tunneling microscopy, researchers have observed a strong reconstruction of the moire lattice in real trilayer samples, leading to the formation of localized twist-angle faults. These localized regions exhibit different electronic structures compared to the background regions, resulting in a doping-dependent, spatially granular electronic landscape.