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Charge-transfer insulation in twisted bilayer graphene

Contributeurs/tricesRademaker, Loukorcid; Mellado, Paula
Publié dansPhysical review. B, vol. 98, no. 23, 235158
Date de publication2018-12-26
Date de mise en ligne2018-12-26
Résumé

We studied the real-space structure of states in twisted bilayer graphene at the magic angle θ=1.08∘. The flat bands close to charge neutrality are composed of a mix of “ring” and “center” orbitals around the AA stacking region. An effective model with localized orbitals is constructed which necessarily includes more than just the four flat bands. Long-range Coulomb interaction causes a charge transfer at half filling of the flat bands from the center to the ring orbitals. Consequently, the Mott phase is a featureless spin-singlet paramagnet. We estimate the effective Heisenberg coupling that favors the singlet coupling to be J=3.3 K, consistent with experimental values. The superconducting state depends on the nature of the dopants: hole-doping yields (p+ip)-wave, whereas electron-doping yields (d+id)-wave pairing symmetry.

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Citation (format ISO)
RADEMAKER, Louk, MELLADO, Paula. Charge-transfer insulation in twisted bilayer graphene. In: Physical review. B, 2018, vol. 98, n° 23, p. 235158. doi: 10.1103/PhysRevB.98.235158
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ISSN du journal2469-9950
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Informations techniques

Création12.12.2022 14:29:00
Première validation12.12.2022 14:29:00
Heure de mise à jour16.03.2023 10:15:32
Changement de statut16.03.2023 10:15:31
Dernière indexation06.05.2024 15:04:52
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