Chiral superconductors, a unique class of unconventional superconductors in which the complex superconducting order parameter winds clockwise or anticlockwise in the momentum space1, represent a topologically non-trivial system with intrinsic time-reversal symmetry breaking (TRSB) and direct implications for topological quantum computing2,3. Intrinsic chiral superconductors are extremely rare, with only a few arguable examples, including UTe2, UPt3 and Sr2RuO4 (refs. 4-7). It has been suggested that chiral superconductivity may exist in non-centrosymmetric superconductors8,9, although such non-centrosymmetry is uncommon in typical solid-state superconductors. Alternatively, chiral molecules with neither mirror nor inversion symmetry have been widely investigated. We suggest that an incorporation of chiral molecules into conventional superconductor lattices could introduce non-centrosymmetry and help realize chiral superconductivity10. Here we explore unconventional superconductivity in chiral molecule intercalated TaS2 hybrid superlattices. Our studies reveal an exceptionally large in-plane upper critical field Bc2,|| well beyond the Pauli paramagnetic limit, a robust π-phase shift in Little-Parks measurements and a field-free superconducting diode effect (SDE). These experimental signatures of unconventional superconductivity suggest that the intriguing interplay between crystalline atomic layers and the self-assembled chiral molecular layers may lead to exotic topological materials. Our study highlights that the hybrid superlattices could lay a versatile path to artificial quantum materials by combining a vast library of layered crystals of rich physical properties with the nearly infinite variations of molecules of designable structural motifs and functional groups11.

California NanoSystems Institute University of California Los Angeles Los Angeles CA USA

Department of Chemistry and Biochemistry University of California Los Angeles Los Angeles CA USA

Department of Electrical and Computer Engineering University of California Los Angeles Los Angeles CA USA

Department of Inorganic Chemistry University of Chemistry and Technology Prague Prague Czech Republic

Department of Materials Science and Engineering University of California Los Angeles Los Angeles CA USA

Department of Physics and Astronomy University of California Los Angeles Los Angeles CA USA

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Kallin, C. & Berlinsky, J. Chiral superconductors. Rep. Prog. Phys. 79, 054502 (2016). PubMed

Bernevig, B. A. & Hughes, T. L. Topological Insulators and Topological Superconductors (Princeton Univ. Press, 2013).

Qi, X.-L. & Zhang, S.-C. Topological insulators and superconductors. Rev. Mod. Phys. 83, 1057–1110 (2011).

Jiao, L. et al. Chiral superconductivity in heavy-fermion metal UTe PubMed

Hayes, I. M. et al. Multicomponent superconducting order parameter in UTe PubMed

Schemm, E. R., Gannon, W. J., Wishne, C. M., Halperin, W. P. & Kapitulnik, A. Observation of broken time-reversal symmetry in the heavy-fermion superconductor UPt PubMed

Jang, J. et al. Observation of half-height magnetization steps in Sr PubMed

Tanaka, Y., Yokoyama, T., Balatsky, A. V. & Nagaosa, N. Theory of topological spin current in noncentrosymmetric superconductors. Phys. Rev. B 79, 060505 (2009).

Yip, S. Noncentrosymmetric superconductors. Annu. Rev. Condens. Matter Phys. 5, 15–33 (2014).

Chen, X.-F. et al. Topologically nontrivial and trivial zero modes in chiral molecules. Phys. Rev. B 108, 035401 (2023).

Aiello, C. D. et al. A chirality-based quantum leap. ACS Nano 16, 4989–5035 (2022). PubMed PMC

Schnyder, A. P., Ryu, S., Furusaki, A. & Ludwig, A. W. W. Classification of topological insulators and superconductors in three spatial dimensions. Phys. Rev. B 78, 195125 (2008).

Sigrist, M. & Ueda, K. Phenomenological theory of unconventional superconductivity. Rev. Mod. Phys. 63, 239–311 (1991).

Fu, L. & Kane, C. L. Superconducting proximity effect and Majorana fermions at the surface of a topological insulator. Phys. Rev. Lett. 100, 96407 (2008).

Zang, Y. et al. Competing energy scales in topological superconducting heterostructures. Nano Lett. 21, 2758–2765 (2021). PubMed PMC

Liu, Y., Xiao, J., Koo, J. & Yan, B. Chirality-driven topological electronic structure of DNA-like materials. Nat. Mater. 20, 638–644 (2021). PubMed PMC

Bian, Z. et al. Hybrid chiral MoS

Ray, K., Ananthavel, S. P., Waldeck, D. H. & Naaman, R. Asymmetric scattering of polarized electrons by organized organic films of chiral molecules. Science 283, 814–816 (1999). PubMed

Göhler, B. et al. Spin selectivity in electron transmission through self-assembled monolayers of double-stranded DNA. Science 331, 894–897 (2011). PubMed

Qian, Q. et al. Chiral molecular intercalation superlattices. Nature 606, 902–908 (2022). PubMed

Ramires, A. Symmetry aspects of chiral superconductors. Contemp. Phys. 63, 71–86 (2022).

Alpern, H. et al. Unconventional superconductivity induced in Nb films by adsorbed chiral molecules. New J. Phys. 18, 113048 (2016).

Sukenik, N. et al. Imprinting chirality on a conventional superconductor. Adv. Phys. Res. 2, 2200072 (2023).

Nakajima, R. et al. Giant spin polarization and a pair of antiparallel spins in a chiral superconductor. Nature 613, 479–484 (2023). PubMed

Meyer, S. F., Howard, R. E., Stewart, G. R., Acrivos, J. V. & Geballe, T. H. Properties of intercalated 2H-NbSe

Zong, P. A. et al. Flexible foil of hybrid TaS

Ribak, A. et al. Chiral superconductivity in the alternate stacking compound 4Hb-TaS

Navarro-Moratalla, E. et al. Enhanced superconductivity in atomically thin TaS PubMed PMC

Yang, Y. et al. Enhanced superconductivity upon weakening of charge density wave transport in 2H-TaS

Gamble, F. R. et al. Intercalation complexes of Lewis bases and layered sulfides: a large class of new superconductors. Science 174, 493–497 (1971). PubMed

Abdel-Hafiez, M. et al. Enhancement of superconductivity under pressure and the magnetic phase diagram of tantalum disulfide single crystals. Sci. Rep. 6, 31824 (2016). PubMed PMC

Zhang, H. et al. Tailored Ising superconductivity in intercalated bulk NbSe

Van Harlingen, D. J. Phase-sensitive tests of the symmetry of the pairing state in the high-temperature superconductors—evidence for [Formula: see text] symmetry. Rev. Mod. Phys. 67, 515–535 (1995).

Little, W. A. & Parks, R. D. Observation of quantum periodicity in the transition temperature of a superconducting cylinder. Phys. Rev. Lett. 9, 9–12 (1962).

Almoalem, A. et al. The observation of π-shifts in the Little-Parks effect in 4Hb-TaS

Vakaryuk, V. & Leggett, A. J. Spin polarization of half-quantum vortex in systems with equal spin pairing. Phys. Rev. Lett. 103, 057003 (2009). PubMed

Li, Y., Xu, X., Lee, M.-H., Chu, M.-W. & Chien, C. L. Observation of half-quantum flux in the unconventional superconductor β-Bi PubMed

Kvashnin, Y. et al. Coexistence of superconductivity and charge density waves in tantalum disulfide: experiment and theory. Phys. Rev. Lett. 125, 186401 (2020). PubMed

Li, L. et al. Superconducting order from disorder in 2H-TaSe

Tang, H. Z., Sun, Q. F., Liu, J. J. & Zhang, Y. T. Majorana zero modes in regular B-form single-stranded DNA proximity-coupled to an s-wave superconductor. Phys. Rev. B 99, 235427 (2019).

Chen, Q., Guo, A. M., Liu, J., Peeters, F. M. & Sun, Q. F. Topological phase transitions and Majorana zero modes in DNA double helix coupled to s-wave superconductors. New J. Phys. 23, 093047 (2021).

Geshkenbein, V. B., Larkin, A. I. & Barone, A. Vortices with half magnetic flux quanta in heavy-fermion superconductors. Phys. Rev. B 36, 235–238 (1987).

Fischer, M. H., Lee, P. A. & Ruhman, J. Mechanism for π phase shifts in Little-Parks experiments: application to 4Hb–TaS

Xu, X., Li, Y. & Chien, C. L. Observation of odd-parity superconductivity with the Geshkenbein-Larkin-Barone composite rings. Phys. Rev. Lett. 132, 56001 (2024).

Ghosh, S. K. et al. Recent progress on superconductors with time-reversal symmetry breaking. J. Phys. Condens. Matter 33, 033001 (2020).

Hou, Y. et al. Ubiquitous superconducting diode effect in superconductor thin films. Phys. Rev. Lett. 131, 027001 (2023). PubMed

Sundaresh, A., Väyrynen, J. I., Lyanda-Geller, Y. & Rokhinson, L. P. Diamagnetic mechanism of critical current non-reciprocity in multilayered superconductors. Nat. Commun. 14, 1628 (2023). PubMed PMC

Yuan, N. F. Q. & Fu, L. Supercurrent diode effect and finite-momentum superconductors. Proc. Natl Acad. Sci. 119, e2119548119 (2022). PubMed PMC

Lin, J. X. et al. Zero-field superconducting diode effect in small-twist-angle trilayer graphene. Nat. Phys. 18, 1221–1227 (2022).

Qiu, G. et al. Emergent ferromagnetism with superconductivity in Fe(Te,Se) van der Waals Josephson junctions. Nat. Commun. 14, 6691 (2023). PubMed PMC

Carapella, G., Sabatino, P., Barone, C., Pagano, S. & Gombos, M. Current driven transition from Abrikosov-Josephson to Josephson-like vortex in mesoscopic lateral S/S′/S superconducting weak links. Sci. Rep. 6, 35694 (2016). PubMed PMC

Haupt, K. Phase Transitions in Transition Metal Dichalcogenides Studied by Femtosecond Electron Diffraction. Thesis, Stellenbosch Univ. (2013).

Wan, Z., Qiu, G. & Duan, X. Replication data for: Unconventional superconductivity in chiral molecule-TaS

Chu, C. G. et al. Broad and colossal edge supercurrent in Dirac semimetal Cd PubMed PMC

Choi, Y. & Bin, et al. Evidence of higher-order topology in multilayer WTe PubMed

Díez-Mérida, J. et al. Symmetry-broken Josephson junctions and superconducting diodes in magic-angle twisted bilayer graphene. Nat. Commun. 14, 2396 (2023). PubMed PMC