Double-edged role of interactions in superconducting twisted bilayer graphene

Nature Physics (2026)Cite this article In conventional superconductors, the formation of Cooper pairs is mediated by phonons. For the superconducting phases in moiré materials, such as that in twisted bilayer graphene, an unresolved question is whether pair formation is driven by electronic interactions, phonons or a combination of both. Here we show that, unlike conventional superconductors, the superconductivity in twisted bilayer graphene is strongly dependent on the dielectric environment. We place twisted bilayer graphene a short distance above a bulk SrTiO3 substrate that has a large and tunable dielectric constant. By raising the dielectric constant in situ in both magic-angle and large-angle devices, we observe steady suppression and eventually a complete extinguishing of the entire superconducting dome. The experimental results are in qualitative agreement with a theoretical model in which the pairing mechanism arises from Coulomb interactions that are screened by plasmons, electron–hole pairs and longitudinal acoustic phonons. Our results highlight the unconventional nature of the superconductivity in this material, the double-edged role played by electronic interactions and the environment in its formation, and their complex interplay with the correlated insulating states.This is a preview of subscription content, access via your institution Access Nature and 54 other Nature Portfolio journals Get Nature+, our best-value online-access subscription $32.99 / 30 days cancel any timeSubscribe to this journal Receive 12 print issues and online access $259.00 per yearonly $21.58 per issueBuy this articleUSD 39.95Prices may be subject to local taxes which are calculated during checkoutThe data that support the findings of this study are available from the corresponding authors on reasonable request. Source data are provided with this paper.The code that supports the findings of this study is available from F.G. upon reasonable request (paco.guinea@imdea.org).Cao, Y. et al. Correlated insulator behaviour at half-filling in magic-angle graphene superlattices. Nature 556, 80 (2018).Article ADS Google Scholar Cao, Y. et al. Unconventional superconductivity in magic-angle graphene superlattices. Nature 556, 43 (2018).Article ADS Google Scholar Bistritzer, R. & MacDonald, A. H. Moiré bands in twisted double-layer graphene. Proc. Natl Acad. Sci. USA 108, 12233 (2011).Article ADS Google Scholar Andrei, E. Y. et al. The marvels of moiré materials. Nat. Rev. Mater. 6, 201 (2021).Article ADS Google Scholar Lau, C. N., Bockrath, M. W., Mak, K. F. & Zhang, F. Reproducibility in the fabrication and physics of moiré materials. Nature 602, 41 (2022).Article ADS Google Scholar Wu, F., MacDonald, A. H. & Martin, I. Theory of phonon-mediated superconductivity in twisted bilayer graphene. Phys. Rev. Lett. 121, 257001 (2018).Article ADS Google Scholar Cea, T. & Guinea, F. Coulomb interaction, phonons, and superconductivity in twisted bilayer graphene. Proc. Natl Acad. Sci. USA 118, e2107874118 (2021).Article Google Scholar Choi, Y. W. & Choi, H. J. Strong electron–phonon coupling, electron–hole asymmetry, and nonadiabaticity in magic-angle twisted bilayer graphene. Phys. Rev. B 98, 241412 (2018).Article ADS Google Scholar Lian, B., Wang, Z. & Bernevig, B. A. Twisted bilayer graphene: a phonon-driven superconductor. Phys. Rev. Lett. 122, 257002 (2019).Article ADS Google Scholar Wu, F., Hwang, E. & Das Sarma, S. Phonon-induced giant linear-in-T resistivity in magic angle twisted bilayer graphene: ordinary strangeness and exotic superconductivity. Phys. Rev. B 99, 165112 (2019).Article ADS Google Scholar Isobe, H., Yuan, N. F. Q. & Fu, L. Unconventional superconductivity and density waves in twisted bilayer graphene. Phys. Rev. X 8, 041041 (2018).

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K.W. and T.T. acknowledge support from the JSPS (KAKENHI Grant Nos, 21H05233 and 23H02052) and the World Premier International Research Center Initiative, MEXT, Japan. A.J.-P., P.A.P. and F.G. acknowledge support from the ‘Severo Ochoa’ Programme for Centres of Excellence in R&D (CEX2020-001039-S/AEI/10.13039/501100011033) and from NOVMOMAT, project PID2022-142162NB-I00 funded by MICIU/AEI/10.13039/501100011033 and by FEDER, UE, as well as financial support through (MAD2D-CM)-MRR MATERIALES AVANZADOS-IMDEA-NC.Department of Physics, The Ohio State University, Columbus, OH, USAXueshi Gao, Aatmaj Rajesh, Emilio Codecido, Daria L. Sharifi, Zheneng Zhang, Youwei Liu, Marc W. Bockrath & Chun Ning LauImdea Nanoscience, Madrid, SpainAlejandro Jimeno-Pozo, Pierre A. Pantaleon & Francisco GuineaLakeshore Cryotronics, Westerville, OH, USAEmilio CodecidoResearch Center for Electronic and Optical Materials, National Institute for Materials Science, Tsukuba, JapanKenji WatanabeResearch Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, JapanTakashi TaniguchiDonostia International Physics Center, Donostia–San Sebastian, SpainFrancisco GuineaSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarX.G. fabricated devices with the help of E.C., D.L.S., Z.Z. and Y.L. X.G. performed the transport measurements. X.G., M.W.B. and C.N.L. analysed the experimental data. A.R. performed the simulation of the charge density. A.J.-P., P.A.P. and F.G. developed the theoretical model and performed the self-consistent Hartree–Fock simulations. K.W. and T.T. provided the hBN crystals. X.G., F.G. and C.N.L. wrote the paper with contributions from all authors.Correspondence to Francisco Guinea or Chun Ning Lau.The authors declare no competing interests.Nature Physics thanks Jiaqi Cai, Jianpeng Liu and Javier Sanchez-Yamagishi for their contribution to the peer review of this work.Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.a.-e. Relative resistance as a function of B and Vtg at Vbg = 15 V, 10 V, 5 V, 0 V and -5V respectively. The relative resistance is defined by the ratio of Rxx and the normal-state resistance, which is measured at B = 0.2 T. Red solid curves indicate Bc, which are defined by the B at which relative resistance is 0.2. At Vbg = -5V, no superconductivity is observed.a.-d. Relative resistance as a function of T and Vtg at Vbg = 15 V, 11 V, 7 V and 4 V respectively. Red solid curves indicate Tc, which are defined by the T at which relative resistance is 0.5. At Vbg = 4 V, no superconductivity is observed.a., b. dVxx/dI (in kΩ) and c., d. d2Vxx/dI2 (in kΩ/nA) as a function of B and I for D1 (at Vbg = 10 V and Vtg = 0.33 V) and D2 (at Vbg = 15 V and Vtg = -2.23 V), respectively.Resistance along the ν=+2 peak vs gate voltage (data taken from Fig. 1e in the main text).Source dataNormalized charge density with respect to charge density at the center σ / σ(0,0) on a 1×1μm2 BLG bottom surface at (Vtg, Vbg) = (0 V, 10 V). At the edge, charge density deviates from the density at the center by < 2%.Supplementary Figs. 1–8, Table 1 and Discussion.Evolution of the band structure of tBLG with a displacement field.Statistical source data.Statistical source data.Statistical source data.Statistical source data.Statistical source data.Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.Reprints and permissionsGao, X., Jimeno-Pozo, A., Pantaleon, P.A. et al. Double-edged role of interactions in superconducting twisted bilayer graphene. Nat. Phys. (2026). https://doi.org/10.1038/s41567-026-03243-1Download citationReceived: 22 December 2024Accepted: 05 March 2026Published: 07 April 2026Version of record: 07 April 2026DOI: https://doi.org/10.1038/s41567-026-03243-1Anyone you share the following link with will be able to read this content:Sorry, a shareable link is not currently available for this article. Provided by the Springer Nature SharedIt content-sharing initiative