Fully gapped superconductivity in magic-angle graphene Cooper-pair islands
Abstract
The mechanism behind superconductivity in magic-angle graphene systems remains an open question. Recent tunnelling and superfluid stiffness measurements have suggested a nodal superconducting gap, but these probes are typically applied to large-area devices, where twist-angle inhomogeneity and disorder can hinder resolving the intrinsic superconducting spectrum. Here we introduce quantum dots in magic-angle twisted bilayer graphene and access a regime where gate-tunable superconductivity competes with strong Coulomb repulsion upon adding an additional carrier to the island. The islands exhibit 2e-periodic Coulomb blockade, revealing a well-defined quasiparticle gap in the island spectrum, inconsistent with the presence of nodes in the order parameter. Within the same device, we also realize coupled superconducting islands and proximitized quantum dots, establishing a monolithic platform for hybrid dot devices. Our results point to a nodeless quasiparticle gap in moiré graphene and demonstrate the potential of mesoscopic hybrid structures to probe their correlated phases.
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BibTeX
@misc{mestretora2026fully,
title = {{Fully gapped superconductivity in magic-angle graphene Cooper-pair islands}},
author = {Alexandra Mestre-Torà and Marta Perego and Clara Galante Agero and Takashi Taniguchi and Kenji Watanabe and Thomas Ihn and Klaus Ensslin and Artem O. Denisov},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2606.14685},
eprint = {2606.14685},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2606.14685},
}
RIS
TY - UNPB
TI - Fully gapped superconductivity in magic-angle graphene Cooper-pair islands
AU - Alexandra Mestre-Torà
AU - Marta Perego
AU - Clara Galante Agero
AU - Takashi Taniguchi
AU - Kenji Watanabe
AU - Thomas Ihn
AU - Klaus Ensslin
AU - Artem O. Denisov
PY - 2026
DA - 2026/10/16
PB - arXiv
DO - 10.48550/arxiv.2606.14685
UR - https://arxiv.org/abs/2606.14685
AB - The mechanism behind superconductivity in magic-angle graphene systems remains an open question. Recent tunnelling and superfluid stiffness measurements have suggested a nodal superconducting gap, but these probes are typically applied to large-area devices, where twist-angle inhomogeneity and disorder can hinder resolving the intrinsic superconducting spectrum. Here we introduce quantum dots in magic-angle twisted bilayer graphene and access a regime where gate-tunable superconductivity competes with strong Coulomb repulsion upon adding an additional carrier to the island. The islands exhibit 2e-periodic Coulomb blockade, revealing a well-defined quasiparticle gap in the island spectrum, inconsistent with the presence of nodes in the order parameter. Within the same device, we also realize coupled superconducting islands and proximitized quantum dots, establishing a monolithic platform for hybrid dot devices. Our results point to a nodeless quasiparticle gap in moiré graphene and demonstrate the potential of mesoscopic hybrid structures to probe their correlated phases.
ER -