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Electrostatic effects, band distortions, and superconductivity in twisted graphene bilayers.

ABSTRACT: Bilayer graphene twisted by a small angle shows a significant charge modulation away from neutrality, as the charge in the narrow bands near the Dirac point is mostly localized in a fraction of the Moiré unit cell. The resulting electrostatic potential leads to a filling-dependent change in the low-energy bands, of a magnitude comparable to or larger than the bandwidth. These modifications can be expressed in terms of new electron-electron interactions, which, when expressed in a local basis, describe electron-assisted hopping terms. These interactions favor superconductivity at certain fillings.

SUBMITTER: Guinea F

PROVIDER: S-EPMC6310832 | biostudies-other | 2018 Dec

REPOSITORIES: biostudies-other

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Electrostatic effects, band distortions, and superconductivity in twisted graphene bilayers.

Guinea Francisco F Walet Niels R NR

Proceedings of the National Academy of Sciences of the United States of America 20181211 52

Bilayer graphene twisted by a small angle shows a significant charge modulation away from neutrality, as the charge in the narrow bands near the Dirac point is mostly localized in a fraction of the Moiré unit cell. The resulting electrostatic potential leads to a filling-dependent change in the low-energy bands, of a magnitude comparable to or larger than the bandwidth. These modifications can be expressed in terms of new electron-electron interactions, which, when expressed in a local basis, de ...[more]

PMID: 30538203

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