Superconductivity in twisted double bilayer graphene stabilized by WSe2
Source abstract
Abstract
Identifying the essential components of superconductivity in graphene-based systems remains a critical problem in two-dimensional materials research. This field is connected to the mysteries that underpin investigations of unconventional superconductivity in condensed-matter physics. Superconductivity has been observed in magic-angle twisted stacks of monolayer graphene but conspicuously not in twisted stacks of bilayer graphene, although both systems host topological flat bands and symmetry-broken states. Here we report the discovery of superconductivity in twisted double bilayer graphene (TDBG) in proximity to WSe2. Samples with twist angles 1.24° and 1.37° superconduct in small pockets of the gate-tuned phase diagram within the valence and conduction band, respectively. Superconductivity emerges from unpolarized phases near van Hove singularities and next to regions with broken isospin symmetry. Our results show the correlation between a high density of states and the emergence of superconductivity in TDBG while revealing a possible role for isospin fluctuations in the pairing.
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References (45)
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1. Cao, Y. et al. Unconventional superconductivity in magic-angle graphene superlattices. Nature 556, 43–50 (2018).10.1038/nature26160 ↗
2. Park, J. M., Cao, Y., Watanabe, K., Taniguchi, T. & Jarillo-Herrero, P. Tunable strongly coupled superconductivity in magic-angle twisted trilayer graphene. Nature 590, 249–255 (2021).10.1038/s41586-021-03192-0 ↗
3. Hao, Z. et al. Electric field–tunable superconductivity in alternating-twist magic-angle trilayer graphene. Science 371, 1133–1138 (2021).10.1126/science.abg0399 ↗
4. Park, J. M. et al. Robust superconductivity in magic-angle multilayer graphene family. Nat. Mater. 21, 877–883 (2022).10.1038/s41563-022-01287-1 ↗
5. Zhang, Y. et al. Promotion of superconductivity in magic-angle graphene multilayers. Science 377, 1538–1543 (2022).10.1126/science.abn8585 ↗
6. Zhou, H., Xie, T., Taniguchi, T., Watanabe, K. & Young, A. F. Superconductivity in rhombohedral trilayer graphene. Nature 598, 434–438 (2021).10.1038/s41586-021-03926-0 ↗
7. Zhou, H. et al. Isospin magnetism and spin-polarized superconductivity in Bernal bilayer graphene. Science 375, 774–778 (2022).10.1126/science.abm8386 ↗
8. Bistritzer, R. & MacDonald, A. H. Moiré bands in twisted double-layer graphene. Proc. Natl Acad. Sci. USA 108, 12233–12237 (2011).10.1073/pnas.1108174108 ↗
9. Balents, L., Dean, C. R., Efetov, D. K. & Young, A. F. Superconductivity and strong correlations in moiré flat bands. Nat. Phys. 16, 725–733 (2020).10.1038/s41567-020-0906-9 ↗
10. You, Y.-Z. & Vishwanath, A. Kohn–Luttinger superconductivity and intervalley coherence in rhombohedral trilayer graphene. Phys. Rev. B 105, 134524 (2022).10.1103/PhysRevB.105.134524 ↗
11. Chou, Y.-Z., Wu, F., Sau, J. D. & Sarma, S. D. Correlation-induced triplet pairing superconductivity in graphene-based moiré systems. Phys. Rev. Lett. 127, 217001 (2021).10.1103/PhysRevLett.127.217001 ↗
12. Lian, B., Wang, Z. & Bernevig, B. A. Twisted bilayer graphene: a phonon-driven superconductor. Phys. Rev. Lett. 122, 257002 (2019).10.1103/PhysRevLett.122.257002 ↗
13. Wu, F., MacDonald, A. H. & Martin, I. Theory of phonon-mediated superconductivity in twisted bilayer graphene. Phys. Rev. Lett. 121, 257001 (2018).10.1103/PhysRevLett.121.257001 ↗
14. Khalaf, E., Chatterjee, S., Bultinck, N., Zaletel, M. P. & Vishwanath, A. Charged skyrmions and topological origin of superconductivity in magic-angle graphene. Sci. Adv. 7, eabf5299 (2021).10.1126/sciadv.abf5299 ↗
15. You, Y.-Z. & Vishwanath, A. Superconductivity from valley fluctuations and approximate SO(4) symmetry in a weak coupling theory of twisted bilayer graphene. NPJ Quantum Mater. 4, 16 (2019).10.1038/s41535-019-0153-4 ↗
16. Lee, J. Y. et al. Theory of correlated insulating behaviour and spin-triplet superconductivity in twisted double bilayer graphene. Nat. Commun. 10, 5333 (2019).10.1038/s41467-019-12981-1 ↗
17. Arora, H. S. et al. Superconductivity in metallic twisted bilayer graphene stabilized by WSe2. Nature 583, 379–384 (2020).10.1038/s41586-020-2473-8 ↗
18. Zhang, Y. et al. Enhanced superconductivity in spin–orbit proximitized bilayer graphene. Nature 613, 268–273 (2023).10.1038/s41586-022-05446-x ↗
19. Holleis, L. et al. Ising superconductivity and nematicity in Bernal bilayer graphene with strong spin orbit coupling. Preprint at arXiv https://doi.org/10.48550/arXiv.2303.00742 (2023).10.48550/arXiv.2303.00742 ↗
20. Lu, X. et al. Superconductors, orbital magnets and correlated states in magic-angle bilayer graphene. Nature 574, 653–657 (2019).10.1038/s41586-019-1695-0 ↗
21. Shen, C. et al. Correlated states in twisted double bilayer graphene. Nat. Phys. 16, 520–525 (2020).10.1038/s41567-020-0825-9 ↗
22. Liu, X. et al. Tunable spin-polarized correlated states in twisted double bilayer graphene. Nature 583, 221–225 (2020).10.1038/s41586-020-2458-7 ↗
23. Cao, Y. et al. Tunable correlated states and spin-polarized phases in twisted bilayer-bilayer graphene. Nature 583, 215–220 (2020).10.1038/s41586-020-2260-6 ↗
24. He, M. et al. Symmetry breaking in twisted double bilayer graphene. Nat. Phys. 17, 26–30 (2021).10.1038/s41567-020-1030-6 ↗
25. Burg, G. W. et al. Correlated insulating states in twisted double bilayer graphene. Phys. Rev. Lett. 123, 197702 (2019).10.1103/PhysRevLett.123.197702 ↗
26. Liu, L. et al. Isospin competitions and valley polarized correlated insulators in twisted double bilayer graphene. Nat. Commun. 13, 3292 (2022).10.1038/s41467-022-30998-x ↗
27. Choi, Y. W. & Choi, H. J. Intrinsic band gap and electrically tunable flat bands in twisted double bilayer graphene. Phys. Rev. B 100, 201402 (2019).10.1103/PhysRevB.100.201402 ↗
28. Cao, Y. et al. Correlated insulator behaviour at half-filling in magic-angle graphene superlattices. Nature 556, 80–84 (2018).10.1038/nature26154 ↗
29. Sharpe, A. L. et al. Emergent ferromagnetism near three-quarters filling in twisted bilayer graphene. Science 365, 605–608 (2019).10.1126/science.aaw3780 ↗
30. Kuiri, M. et al. Spontaneous time-reversal symmetry breaking in twisted double bilayer graphene. Nat. Commun. 13, 6468 (2022).10.1038/s41467-022-34192-x ↗
31. Koshino, M. Band structure and topological properties of twisted double bilayer graphene. Phys. Rev. B 99, 235406 (2019).10.1103/PhysRevB.99.235406 ↗
32. Zhang, Y.-H., Mao, D., Cao, Y., Jarillo-Herrero, P. & Senthil, T. Nearly flat Chern bands in moiré superlattices. Phys. Rev. B 99, 075127 (2019).10.1103/PhysRevB.99.075127 ↗
33. Samajdar, R. & Scheurer, M. S. Microscopic pairing mechanism, order parameter, and disorder sensitivity in moiré superlattices: applications to twisted double-bilayer graphene. Phys. Rev. B 102, 064501 (2020).10.1103/PhysRevB.102.064501 ↗
34. Hsu, Y.-T., Wu, F. & Sarma, S. D. Topological superconductivity, ferromagnetism, and valley-polarized phases in moiré systems: renormalization group analysis for twisted double bilayer graphene. Phys. Rev. B 102, 085103 (2020).10.1103/PhysRevB.102.085103 ↗
35. Lin, J.-X. et al. Spin–orbit-driven ferromagnetism at half moiré filling in magic-angle twisted bilayer graphene. Science 375, 437–441 (2022).10.1126/science.abh2889 ↗
36. Maharaj, A. V., Esterlis, I., Zhang, Y., Ramshaw, B. J. & Kivelson, S. A. Hall number across a van Hove singularity. Phys. Rev. B 96, 045132 (2017).10.1103/PhysRevB.96.045132 ↗
37. Tinkham, M. Introduction to Superconductivity (Courier Corporation, 2004).
38. Clogston, A. M. Upper limit for the critical field in hard superconductors. Phys. Rev. Lett. 9, 266–267 (1962).10.1103/PhysRevLett.9.266 ↗
39. Cao, Y., Park, J. M., Watanabe, K., Taniguchi, T. & Jarillo-Herrero, P. Pauli-limit violation and re-entrant superconductivity in moiré graphene. Nature 595, 526–531 (2021).10.1038/s41586-021-03685-y ↗
40. Huang, C., Wei, N., Qin, W. & MacDonald, A. H. Pseudospin paramagnons and the superconducting dome in magic angle twisted bilayer graphene. Phys. Rev. Lett. 129, 187001 (2022).10.1103/PhysRevLett.129.187001 ↗
41. Chou, Y.-Z., Wu, F. & Sarma, S. D. Enhanced superconductivity through virtual tunneling in Bernal bilayer graphene coupled to WSe2. Phys. Rev. B 106, L180502 (2022).10.1103/PhysRevB.106.L180502 ↗
42. Wang, Z. et al. Origin and magnitude of ‘designer’ spin–orbit interaction in graphene on semiconducting transition metal dichalcogenides. Phys. Rev. X 6, 041020 (2016).
43. Klemm, R. A., Luther, A. & Beasley, M. Theory of the upper critical field in layered superconductors. Phys. Rev. B 12, 877 (1975).10.1103/PhysRevB.12.877 ↗
44. Lake, E., Patri, A. S. & Senthil, T. Pairing symmetry of twisted bilayer graphene: a phenomenological synthesis. Phys. Rev. B 106, 104506 (2022).10.1103/PhysRevB.106.104506 ↗
45. Kim, K. et al. van der Waals heterostructures with high accuracy rotational alignment. Nano Lett. 16, 1989–1995 (2016).10.1021/acs.nanolett.5b05263 ↗