Twistons in a Sea of Magic

TL;DR

This study uses low temperature scanning tunneling microscopy to investigate the structural and electronic properties of magic angle twisted trilayer graphene, revealing twistons as key defects influencing superconductivity.

Contribution

It uncovers the presence of twistons as moiré lattice defects in TTG, linking structural reconstructions to superconducting behavior and disorder effects.

Findings

Identification of twistons as localized twist angle faults

Correlation between twiston distribution and superconducting dome

Observation of layer reconstruction into near-magic angle domains

Abstract

Magic angle twisted trilayer graphene (TTG) has recently emerged as a new platform to engineer strongly correlated flat bands. Here, we reveal the structural and electronic properties of TTG using low temperature scanning tunneling microscopy at twist angles for which superconductivity has been observed. Real trilayer samples deviate from their idealized structure due to a strong reconstruction of the moir\'e lattice, which locks layers into near-magic angle, mirror symmetric domains comparable in size to the superconducting coherence length. The price for this magic relaxation is the introduction of an array of localized twist angle faults, termed twistons. These novel, gate-tunable moir\'e defects offer a natural explanation for the superconducting dome observed in transport and provide an avenue to probe superconducting pairing mechanisms through disorder tuning.