Abstract
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. 4,5,6,7). 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.
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Data availability
The original data files that support the findings of this study are available on the Zenodo public database at https://doi.org/10.5281/zenodo.11106945 (ref. 53) and from X.D.
References
Kallin, C. & Berlinsky, J. Chiral superconductors. Rep. Prog. Phys. 79, 054502 (2016).
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 UTe2. Nature 579, 523–527 (2020).
Hayes, I. M. et al. Multicomponent superconducting order parameter in UTe2. Science 373, 797–801 (2021).
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 UPt3. Science 345, 190–193 (2014).
Jang, J. et al. Observation of half-height magnetization steps in Sr2RuO4. Science 331, 186–188 (2011).
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).
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).
Liu, Y., Xiao, J., Koo, J. & Yan, B. Chirality-driven topological electronic structure of DNA-like materials. Nat. Mater. 20, 638–644 (2021).
Bian, Z. et al. Hybrid chiral MoS2 layers for spin‐polarized charge transport and spin‐dependent electrocatalytic applications. Adv. Sci. 9, 2201063 (2022).
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).
Göhler, B. et al. Spin selectivity in electron transmission through self-assembled monolayers of double-stranded DNA. Science 331, 894–897 (2011).
Qian, Q. et al. Chiral molecular intercalation superlattices. Nature 606, 902–908 (2022).
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).
Meyer, S. F., Howard, R. E., Stewart, G. R., Acrivos, J. V. & Geballe, T. H. Properties of intercalated 2H-NbSe2, 4Hb-TaS2, and 1T-TaS2. J. Chem. Phys. 62, 4411–4419 (1974).
Zong, P. A. et al. Flexible foil of hybrid TaS2/organic superlattice: fabrication and electrical properties. Small 16, 1901901 (2020).
Ribak, A. et al. Chiral superconductivity in the alternate stacking compound 4Hb-TaS2. Sci. Adv. 6, eaax9480 (2019).
Navarro-Moratalla, E. et al. Enhanced superconductivity in atomically thin TaS2. Nat. Commun. 7, 11043 (2016).
Yang, Y. et al. Enhanced superconductivity upon weakening of charge density wave transport in 2H-TaS2 in the two-dimensional limit. Phys. Rev. B 98, 035203 (2018).
Gamble, F. R. et al. Intercalation complexes of Lewis bases and layered sulfides: a large class of new superconductors. Science 174, 493–497 (1971).
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).
Zhang, H. et al. Tailored Ising superconductivity in intercalated bulk NbSe2. Nat. Phys. 18, 1425–1430 (2022).
Van Harlingen, D. J. Phase-sensitive tests of the symmetry of the pairing state in the high-temperature superconductors—evidence for \({d}_{{x}^{2}-{y}^{2}}\) 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-TaS2. Nat. Commun. 15, 4623 (2024).
Vakaryuk, V. & Leggett, A. J. Spin polarization of half-quantum vortex in systems with equal spin pairing. Phys. Rev. Lett. 103, 057003 (2009).
Li, Y., Xu, X., Lee, M.-H., Chu, M.-W. & Chien, C. L. Observation of half-quantum flux in the unconventional superconductor β-Bi2Pd. Science 366, 238–241 (2019).
Kvashnin, Y. et al. Coexistence of superconductivity and charge density waves in tantalum disulfide: experiment and theory. Phys. Rev. Lett. 125, 186401 (2020).
Li, L. et al. Superconducting order from disorder in 2H-TaSe2−xSx. npj Quantum Mater. 2, 11 (2017).
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–TaS2 and to 2H–TaS2 intercalated with chiral molecules. Phys. Rev. B 108, L180505 (2023).
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).
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).
Yuan, N. F. Q. & Fu, L. Supercurrent diode effect and finite-momentum superconductors. Proc. Natl Acad. Sci. 119, e2119548119 (2022).
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).
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).
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-TaS2 hybrid superlattices. Zenodo https://doi.org/10.5281/zenodo.11106945 (2024).
Chu, C. G. et al. Broad and colossal edge supercurrent in Dirac semimetal Cd3As2 Josephson junctions. Nat. Commun. 14, 6162 (2023).
Choi, Y. & Bin, et al. Evidence of higher-order topology in multilayer WTe2 from Josephson coupling through anisotropic hinge states. Nat. Mater. 19, 974–979 (2020).
Díez-Mérida, J. et al. Symmetry-broken Josephson junctions and superconducting diodes in magic-angle twisted bilayer graphene. Nat. Commun. 14, 2396 (2023).
Acknowledgements
We acknowledge the helpful discussions with X. Cai, L. Fu, G. B. Halász, C. Hua, Y. Ping and L. P. Rokhinson. We would also like to thank J. Fang for the kind support during the measurements. X.D. acknowledges the support from the Office of Naval Research through grant no. N00014-22-1-2631. K.L.W. and G.Q. acknowledge the support from the Army Research Office under the Multidisciplinary University Research Initiative through grant no. W911NF2020166. Z.S. acknowledges the support from the ERC CZ programme (project LL2101) from the Ministry of Education Youth and Sports and by the project Advanced Functional Nanorobots (reg. no. CZ.02.1.01/0.0/0.0/15_003/0000444 financed by the EFRR). A portion of this work was performed at the National High Magnetic Field Laboratory, which is supported by National Science Foundation Cooperative Agreement No. DMR-2128556 and the State of Florida.
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X.D. conceived the research. X.D., Z.W. and G.Q. designed the experiments. H.R. prepared the chiral molecule intercalated TaS2. Z.W. and G.Q. fabricated the devices. Y.L., B.Z., D.X. and L.W. assisted in device fabrications. Z.W., G.Q. and Q.Q. performed the electrical measurements and data analysis. Z.S. provided the TaS2 crystals. Jingy.Z., Jingx.Z. and T.-H.Y. contributed to discussions and data analysis. X.D. K.L.W. and Y.H. supervised the research. Z.W., G.Q. and X.D. co-wrote the manuscript, with input from all authors. All authors discussed the results and commented on the manuscript.
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Extended data figures and tables
Extended Data Fig. 1 XRD patterns of the R-MBA and S-MBA intercalated TaS2.
XRD patterns of the chiral R-MBA/TaS2 and S-MBA/TaS2 CMISs and pristine TaS2. The resulting intercalation superlattices exhibit a notable expansion of interlayer spacing from 5.8 Å to 11.7 Å, with the sharp diffraction peaks highlighting the formation of highly ordered superlattice structures.
Extended Data Fig. 2 Replot of Fig. 2c with forward (solid lines) and reverse (dashed lines) scan directions.
No obvious hysteresis behaviour was observed between different scan directions. Magnetic-field loops were scanned back and forth and no magnetic-hysteresis behaviour was observed. To rule out the possible time-domain resistance fluctuation, each curve was repeated with different scanning rates and the oscillations remained the same.
Extended Data Fig. 3 Robust π-phase shift of chiral molecule intercalated device after thermal cycling.
a, The Little–Parks effect in the same device as in Fig. 2c,d remeasured after being warmed up above Tc and cooled to the base temperature. A robust π-phase shift can be repeated after thermal cycling. b, The colour mapping of the Little–Parks oscillation amplitudes of the same device at slightly higher temperature. The colour mapping showed a gradual evolution from pure π-shift states at lower temperature (resistance maxima at 0, ±1Φ0, ±2Φ0, ±3Φ0 at 1.3 K) to the half-period states at higher temperature (resistance maxima at ±0.5Φ0, ±1.0Φ0, ±1.5Φ0, ±2.0Φ0 at 1.475 K). The observed half-period in our system at a moderately higher temperature is distinct from the domain-boundary-induced π-phase shift reported previously44, in which the zero-phase and π-phase peaks do not typically mix together to produce half-periods.
Extended Data Fig. 4 π-phase shift of S-MBA intercalated device.
Four-terminal resistance (logarithmic scale) of an S-MBA intercalated 2H–TaS2 Little–Parks device as a function of magnetic field at different temperatures. The colour map in Fig. 2e was extracted from these data.
Extended Data Fig. 5 XRD pattern of the achiral molecule intercalated TaS2.
XRD patterns of the achiral TEAB intercalated2–TaS2 CMISs and pristine TaS2 showing sharp diffraction peaks with a notable expansion of interlayer spacing from 5.8 to 11.1 Å, highlighting the formation of highly ordered superlattice structures.
Extended Data Fig. 6 R–T curve of TEAB intercalated TaS2 ring devices.
Temperature dependence of the four-terminal resistance of TEAB intercalated TaS2 ring devices.
Extended Data Fig. 7 More achiral molecule intercalated TaS2 devices.
a,c, Four-terminal resistance (logarithmic scale) of two further achiral intercalated 2H–TaS2 Little–Parks devices as a function of magnetic field at different temperatures. b,d, Colour mapping of the Little–Parks oscillation amplitudes of achiral molecule intercalated devices as a function of temperature and external magnetic flux. No phase shift was observed among a total of four achiral molecule intercalated TaS2 devices that showed Little–Parks effect, highlighting the essential role of molecular chirality in achieving π-phase shift.
Extended Data Fig. 8 Relaxed structure of MBA and TEAB interacted TaS2.
a, Side view of the MBA intercalated 2H–TaS2. b, Top view of the MBA intercalated 2H–TaS2. The bulk chiral intercalated TaS2 belongs to the P321 space group. c, Side view of the TEAB intercalated 2H–TaS2. d, Top view of the TEAB intercalated 2H–TaS2. The bulk achiral intercalated TaS2 belongs to the \({\rm{P}}\bar{3}{\rm{m}}1\) space group.
Extended Data Fig. 9 Further analysis of field-free SDE.
a, ΔIc versus magnetic field in chiral molecule intercalated TaS2. b, ΔIc versus field in chiral molecule intercalated TaS2, which can be resolved with a combination of odd (c) and even (d) function components. c, Phenomenological calculated field-mediated critical current differences ΔIc-odd as a function of magnetic field. d, Field-free diode component ΔIc-even as a function of magnetic field, which shows oscillation patterns (magenta). We note that there is an apparent oscillation with several peaks in the ΔIc-even versus B scan, with a Fraunhofer-like pattern. The overall amplitude of ΔIc-even decays more slowly with magnetic field than a typical Fraunhofer pattern (in which the peak amplitude scales with 1/B), but fits well with a non-uniform supercurrent distribution favouring an edge-state transport54,55,56. The dashed lines are fitting of a Fraunhofer pattern with uniform current distribution (red) or with edge current distribution (blue).
Extended Data Fig. 10 SDE in chiral molecule interacted TaS2 with different field-cooling procedures.
a, Ic versus field after 0 T (top), 1 T (middle) and −1 T (bottom) field cooling. The diode-effect polarity is independent of field-cooling history. The samples were heated up to 4 K so that the sample returned to normal state to make sure the magnetic impurities, if any, will be magnetized without Meissner effect. b, V–I curves at zero field after 0 T (top), 1 T (middle) and −1 T (bottom) field cooling. Positive diode effects (Ic+ > Ic−) are observed in all cases after different field-cooling procedures.
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Wan, Z., Qiu, G., Ren, H. et al. Unconventional superconductivity in chiral molecule–TaS2 hybrid superlattices. Nature 632, 69–74 (2024). https://doi.org/10.1038/s41586-024-07625-4
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DOI: https://doi.org/10.1038/s41586-024-07625-4
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