- Physical Review Journals
All JournalsPhysics Magazine

Physical Review X

Reuse & Permissions

It is not necessary to obtain permission to reuse this article or its components as it is available under the terms of the Creative Commons Attribution 4.0 International license. This license permits unrestricted use, distribution, and reproduction in any medium, provided attribution to the author(s) and the published article's title, journal citation, and DOI are maintained. Please note that some figures may have been included with permission from other third parties. It is your responsibility to obtain the proper permission from the rights holder directly for these figures.

Export citation

Export citation

Choose format for download:

Download Citation
  • Open Access

Microscopic Fingerprint of Chiral Superconductivity

Xuefeng Wu1,*, Xuan Hao1,2,*, Zhuo Chen3,*, Yuchang Cai3, Minghao Wu2, Congrun Chen2, Kedong Wang2,†, Fangfei Ming4,‡, Steven Johnston3,5 et al.

Rui-Xing Zhang3,5,6,§ and Hanno H. Weitering3,5,∥

  • *These authors contributed equally to this work.
  • †Contact author: wangkd@sustech.edu.cn
  • ‡Contact author: mingff@mail.sysu.edu.cn
  • §Contact author: ruixing@utk.edu
  • ∥Contact author: hanno@utk.edu
PDF

Phys. Rev. X 16, 011026 – Published 17 February, 2026

DOI: https://doi.org/10.1103/jmmf-mpr8

Abstract

Chiral superconductors have long been theorized to break time-reversal symmetry and support exotic topological features such as Majorana modes and spontaneous edge currents, promising ingredients for quantum technologies. Although several unconventional superconductors may exhibit time-reversal symmetry breaking, clear microscopic evidence of chiral pairing has remained out of reach. In this work, we demonstrate direct real-space signatures of chiral superconductivity in a single atomic layer of tin on Si(111). Using quasiparticle interference imaging, we detected symmetry-locked nodal and antinodal points in the Bogoliubov quasiparticle wave function, tightly bound to atomic point defects in the tin lattice. These nodal features, along with their surrounding texture, form a distinct real-space pattern exhibiting a clear and exclusive hallmark of chiral superconductivity. Our findings, reinforced by analytical theory and numerical simulations, offer unambiguous evidence of chiral pairing in a two-dimensional material.

View figure in article

Physics Subject Headings (PhySH)

Popular Summary

Demonstrating chiral superconductivity is a major experimental challenge because the intrinsic handedness of its Cooper pairs is difficult to extract from measurements. We address this by imaging a monatomic layer of tin on silicon and observing the quantum interference patterns formed when superconducting electrons scatter from atomic-scale defects. Our experiments reveal distinctive nodal patterns in the electron density whose symmetry matches theoretical predictions for chiral pairing. These nodal features remain locked to the defects regardless of their microscopic origin—a robustness that serves as a specific signature of chiral superconducting states. Our results provide evidence for this exotic form of pairing and introduce a novel real-space approach to identifying superconducting symmetries in low-dimensional materials.

Article Text

References (52)

  1. N. Read and D. Green, Paired states of fermions in two dimensions with breaking of parity and time-reversal symmetries and the fractional quantum Hall effect, Phys. Rev. B 61, 10267 (2000).
  2. C. Nayak, S. H. Simon, A. Stern, M. Freedman, and S. Das Sarma, Non-Abelian anyons and topological quantum computation, Rev. Mod. Phys. 80, 1083 (2008).
  3. M. Sato and Y. Ando, Topological superconductors: A review, Rep. Prog. Phys. 80, 076501 (2017).
  4. G. M. Luke, Y. Fudamoto, K. M. Kojima, M. I. Larkin, J. Merrin, B. Nachumi, Y. J. Uemura, Y. Maeno, Z. Q. Mao, Y. Mori, H. Nakamura, and M. Sigrist, Time-reversal symmetry-breaking superconductivity in Sr2RuO4, Nature (London) 394, 558 (1998).
  5. A. P. Mackenzie and Y. Maeno, The superconductivity of Sr2RuO4 and the physics of spin-triplet pairing, Rev. Mod. Phys. 75, 657 (2003).
  6. J. Xia, Y. Maeno, P. T. Beyersdorf, M. M. Fejer, and A. Kapitulnik, High resolution polar Kerr effect measurements of Sr2RuO4: Evidence for broken time-reversal symmetry in the superconducting state, Phys. Rev. Lett. 97, 167002 (2006).
  7. A. Pustogow, Y. Luo, A. Chronister, Y.-S. Su, D. A. Sokolov, F. Jerzembeck, A. P. Mackenzie, C. W. Hicks, N. Kikugawa, S. Raghu, E. D. Bauer, and S. E. Brown, Constraints on the superconducting order parameter in Sr2RuO4 from oxygen-17 nuclear magnetic resonance, Nature (London) 574, 72 (2019).
  8. A. Chronister, A. Pustogow, N. Kikugawa, D. A. Sokolov, F. Jerzembeck, C. W. Hicks, A. P. Mackenzie, E. D. Bauer, and S. E. Brown, Evidence for even parity unconventional superconductivity in Sr2RuO4, Proc. Natl. Acad. Sci. U.S.A. 118, e2025313118 (2021).
  9. D. Aoki, A. Nakamura, F. Honda, D. Li, Y. Homma, Y. Shimizu, Y. J. Sato, G. Knebel, J.-P. Brison, A. Pourret, D. Braithwaite, G. Lapertot, Q. Niu, M. Vališka, H. Harima, and J. Flouquet, Unconventional superconductivity in heavy fermion UTe2, J. Phys. Soc. Jpn. 88, 043702 (2019).
  10. S. Ran, C. Eckberg, Q.-P. Ding, Y. Furukawa, T. Metz, S. R. Saha, I.-L. Liu, M. Zic, H. Kim, J. Paglione, and N. P. Butch, Nearly ferromagnetic spin-triplet superconductivity, Science 365, 684 (2019).
  11. Q. Gu, S. Wang, J. P. Carroll, K. Zhussupbekov, C. Broyles, S. Ran, N. P. Butch, J. A. Horn, S. Saha, J. Paglione, X. Liu, J. C. S. Davis, and D.-H. Lee, Pair wave function symmetry in UTe2 from zero-energy surface state visualization, Science 388, 938 (2025).
  12. E. R. Schemm, W. J. Gannon, C. M. Wishne, W. P. Halperin, and A. Kapitulnik, Observation of broken time-reversal symmetry in the heavy-fermion superconductor UPt3, Science 345, 190 (2014).
  13. K. E. Avers, W. J. Gannon, S. J. Kuhn, W. P. Halperin, J. A. Sauls, L. DeBeer-Schmitt, C. D. Dewhurst, J. Gavilano, G. Nagy, U. Gasser, and M. R. Eskildsen, Broken time-reversal symmetry in the topological superconductor UPt3, Nat. Phys. 16, 531 (2020).
  14. A. Ribak, R. M. Skiff, M. Mograbi, P. K. Rout, M. H. Fischer, J. Ruhman, K. Chashka, Y. Dagan, and A. Kanigel, Chiral superconductivity in the alternate stacking compound 4Hb-TaS2, Sci. Adv. 6, eaax9480 (2020).
  15. S. Y. F. Zhao, X. Cui, P. A. Volkov, H. Yoo, S. Lee, J. A. Gardener, A. J. Akey, R. Engelke, Y. Ronen, R. Zhong, G. Gu, S. Plugge, T. Tummuru, M. Kim, M. Franz, J. H. Pixley, N. Poccia, and P. Kim, Time-reversal symmetry breaking superconductivity between twisted cuprate superconductors, Science 382, 1422 (2023).
  16. Z. Wan, G. Qiu, H. Ren, Q. Qian, Y. Li, D. Xu, J. Zhou, J. Zhou, B. Zhou, L. Wang, T.-H. Yang, Z. Sofer, Y. Huang, K. L. Wang, and X. Duan, Unconventional superconductivity in chiral molecule–TaS2 hybrid superlattices, Nature (London) 632, 69 (2024).
  17. T. Han, Z. Lu, Z. Hadjri, L. Shi, Z. Wu, W. Xu, Y. Yao, A. A. Cotten, O. Sharifi Sedeh, H. Weldeyesus, J. Yang, J. Seo, S. Ye, M. Zhou, H. Liu, G. Shi, Z. Hua, K. Watanabe, T. Taniguchi, P. Xiong, D. M. Zumbühl, L. Fu, and L. Ju, Signatures of chiral superconductivity in rhombohedral graphene, Nature (London) 643, 654 (2025).
  18. A. Soumyanarayanan, M. M. Yee, Y. He, J. van Wezel, D. J. Rahn, K. Rossnagel, E. W. Hudson, M. R. Norman, and J. E. Hoffman, Quantum phase transition from triangular to stripe charge order in NbSe2, Proc. Natl. Acad. Sci. U.S.A. 110, 1623 (2013).
  19. Z. Wang, J. O. Rodriguez, L. Jiao, S. Howard, M. Graham, G. D. Gu, T. L. Hughes, D. K. Morr, and V. Madhavan, Evidence for dispersing 1D Majorana channels in an iron-based superconductor, Science 367, 104 (2020).
  20. T. Hanaguri, S. Niitaka, K. Kuroki, and H. Takagi, Unconventional s-wave superconductivity in Fe(Se,Te), Science 328, 474 (2010).
  21. K. McElroy, J. Lee, J. A. Slezak, D.-H. Lee, H. Eisaki, S. Uchida, and J. C. Davis, Atomic-scale sources and mechanism of nanoscale electronic disorder in Bi2Sr2CaCu2O8+δ, Science 309, 1048 (2005).
  22. M. P. Allan, F. Massee, D. K. Morr, J. Van Dyke, A. W. Rost, A. P. Mackenzie, C. Petrovic, and J. C. Davis, Imaging cooper pairing of heavy fermions in CeCoIn5, Nat. Phys. 9, 468 (2013).
  23. Y. Gao, Y. Wang, T. Zhou, H. Huang, and Q.-H. Wang, Possible pairing symmetry in the FeSe-based superconductors determined by quasiparticle interference, Phys. Rev. Lett. 121, 267005 (2018).
  24. J. Böker, P. A. Volkov, P. J. Hirschfeld, and I. Eremin, Quasiparticle interference and symmetry of superconducting order parameter in strongly electron-doped iron-based superconductors, New J. Phys. 21, 083021 (2019).
  25. A. Kreisel, P. Choubey, T. Berlijn, W. Ku, B. M. Andersen, and P. J. Hirschfeld, Interpretation of scanning tunneling quasiparticle interference and impurity states in cuprates, Phys. Rev. Lett. 114, 217002 (2015).
  26. F. Ming, S. Johnston, D. Mulugeta, T. S. Smith, P. Vilmercati, G. Lee, T. A. Maier, P. C. Snijders, and H. H. Weitering, Realization of a hole-doped Mott insulator on a triangular silicon lattice, Phys. Rev. Lett. 119, 266802 (2017).
  27. G. Li, P. Höpfner, J. Schäfer, C. Blumenstein, S. Meyer, A. Bostwick, E. Rotenberg, R. Claessen, and W. Hanke, Magnetic order in a frustrated two-dimensional atom lattice at a semiconductor surface, Nat. Commun. 4, 1620 (2013).
  28. X. Wu, F. Ming, T. S. Smith, G. Liu, F. Ye, K. Wang, S. Johnston, and H. H. Weitering, Superconductivity in a hole-doped Mott-insulating triangular adatom layer on a Silicon surface, Phys. Rev. Lett. 125, 117001 (2020).
  29. F. Ming, X. Wu, C. Chen, K. D. Wang, P. Mai, T. A. Maier, J. Strockoz, J. W. F. Venderbos, C. González, J. Ortega, S. Johnston, and H. H. Weitering, Evidence for chiral superconductivity on a silicon surface, Nat. Phys. 19, 500 (2023).
  30. G. Profeta and E. Tosatti, Triangular Mott-Hubbard insulator phases of Sn/Si(111) and Sn/Ge(111) surfaces, Phys. Rev. Lett. 98, 086401 (2007).
  31. S. Modesti, L. Petaccia, G. Ceballos, I. Vobornik, G. Panaccione, G. Rossi, L. Ottaviano, R. Larciprete, S. Lizzit, and A. Goldoni, Insulating ground state of Sn/Si(111)−(3×3)R30°, Phys. Rev. Lett. 98, 126401 (2007).
  32. M. Jäger, C. Brand, A. P. Weber, M. Fanciulli, J. H. Dil, H. Pfnür, and C. Tegenkamp, α−Sn phase on Si(111): Spin texture of a two-dimensional Mott state, Phys. Rev. B 98, 165422 (2018).
  33. D. J. Scalapino, A common thread: The pairing interaction for unconventional superconductors, Rev. Mod. Phys. 84, 1383 (2012).
  34. M. Sigrist and K. Ueda, Phenomenological theory of unconventional superconductivity, Rev. Mod. Phys. 63, 239 (1991).
  35. C. Kallin and J. Berlinsky, Chiral superconductors, Rep. Prog. Phys. 79, 054502 (2016).
  36. V. Zampronio and T. Macrì, Chiral superconductivity in the doped triangular-lattice Fermi-Hubbard model in two dimensions, Quantum 7, 1061 (2023).
  37. X. Cao, T. Ayral, Z. Zhong, O. Parcollet, D. Manske, and P. Hansmann, Chiral d-wave superconductivity in a triangular surface lattice mediated by long-range interaction, Phys. Rev. B 97, 155145 (2018).
  38. M. Uldemolins, A. Mesaros, and P. Simon, Quasiparticle focusing of bound states in two-dimensional s-wave superconductors, Phys. Rev. B 105, 144503 (2022).
  39. M. Ruby, Y. Peng, F. von Oppen, B. W. Heinrich, and K. J. Franke, Orbital picture of Yu-Shiba-Rusinov multiplets, Phys. Rev. Lett. 117, 186801 (2016).
  40. G. C. Ménard, S. Guissart, C. Brun, S. Pons, V. S. Stolyarov, F. Debontridder, M. V. Leclerc, E. Janod, L. Cario, D. Roditchev, P. Simon, and T. Cren, Coherent long-range magnetic bound states in a superconductor, Nat. Phys. 11, 1013 (2015).
  41. H. Kim, L. Rózsa, D. Schreyer, E. Simon, and R. Wiesendanger, Long-range focusing of magnetic bound states in superconducting lanthanum, Nat. Commun. 11, 4573 (2020).
  42. Q.-H. Wang and Z. D. Wang, Impurity and interface bound states in dx2−y2+idxy and px+ipy superconductors, Phys. Rev. B 69, 092502 (2004).
  43. M. Mashkoori, K. Björnson, and A. M. Black-Schaffer, Impurity bound states in fully gapped d-wave superconductors with subdominant order parameters, Sci. Rep. 7, 44107 (2017).
  44. L. Marchetti, M. Bunney, D. Di Sante, and S. Rachel, Electronic structure, spin-orbit interaction, and electron-phonon coupling of triangular adatom lattices on semiconductor substrates, Phys. Rev. B 111, 125115 (2025).
  45. Y. Cai and R.-X. Zhang, Deciphering chiral superconductivity via impurity bound states, arXiv:2506.20842.
  46. S. Wolf, D. Di Sante, T. Schwemmer, R. Thomale, and S. Rachel, Triplet superconductivity from nonlocal Coulomb repulsion in an atomic Sn layer deposited onto a Si(111) substrate, Phys. Rev. Lett. 128, 167002 (2022).
  47. M. Biderang, M.-H. Zare, and J. Sirker, Topological superconductivity in Sn/Si(111) driven by nonlocal Coulomb interactions, Phys. Rev. B 106, 054514 (2022).
  48. K. W. Kim and T. Pereg-Barnea, Interplay between superconductivity and magnetism in triangular lattices, Phys. Rev. B 108, 195113 (2023).
  49. R.-X. Zhang, F. Ming, and H. H. Weitering, Dataset for Microscopic fingerprint of chiral superconductivity, 10.5281/zenodo.15741993 (2025).
  50. F. Pientka, L. I. Glazman, and F. von Oppen, Topological superconducting phase in helical Shiba chains, Phys. Rev. B 88, 155420 (2013).
  51. V. Kaladzhyan, C. Bena, and P. Simon, Asymptotic behavior of impurity-induced bound states in low-dimensional topological superconductors, J. Phys. Condens. Matter 28, 485701 (2016).
  52. S. T. Jemander, N. Lin, H. M. Zhang, R. I. G. Uhrberg, and G. V. Hansson, An STM study of the surface defects of the (3×3)−Sn/Si(111) surface, Surf. Sci. 475, 181 (2001).

Outline

Information

Phys. Rev. X 16, 011026– Published 17 February, 2026
  • Received 25 July 2025
  • Revised 26 December 2025
  • Accepted 15 January 2026
Crossmark - Check for updates button
Creative Commons Logo

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.

Published by the American Physical Society

Sign In to Your Journals Account

Filter

Filter

Article Lookup

Enter a citation