Field-induced superconductivity in a magnetically doped two-dimensional crystal

Nature Physics (2026)Cite this article Magnetic-field-induced superconductivity is a rare property in nature because conventional Cooper pairs with spin-singlet symmetry are expected to be sensitive to perturbations that break time-reversal symmetry. However, in some cases, the interplay between finite magnetic fields and ions can be engineered to bring about superconductivity, despite the usual expectation. Here we demonstrate a magnetic-field-induced superconducting dome in a two-dimensional crystal of ultrathin LaSb2 doped with dilute Ce paramagnetic impurities. The reduced dimensionality of the structure enables the use of an in-plane magnetic field to dynamically suppress spin fluctuations on the Ce site, and this leads to an anomalous enhancement of the critical temperature with increasing field. By modelling the spin scattering dynamics across the experimental parameter space, we gain insights into the complex nature of paramagnetic impurities in magnetic fields at low temperature and how their manipulation can result in the ability to tune between competing magnetic pair-breaking regimes. Demonstrating this effect in a two-dimensional crystalline setting invites the application of similar approaches to unconventional forms of superconductivity.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 full experimental dataset is available via the Caltech Data server at https://data.caltech.edu/. Source data are provided with this paper.Anderson, P. W. Theory of dirty superconductors. J. Phys. Chem. Solids 11, 26–30 (1959).Article ADS Google Scholar Zhou, B. T., Yuan, N. F. Q., Jiang, H. L. & Law, K. T. Ising superconductivity and Majorana fermions in transition-metal dichalcogenides. Phys. Rev. B 93, 180501 (2016).Article ADS Google Scholar Balian, R. & Werthamer, N. R. Superconductivity with pairs in a relative p wave. Phys. Rev. 131, 1553 (1963).Article ADS Google Scholar Fulde, P. & Ferrell, R. A. Superconductivity in a strong spin-exchange field. Phys. Rev. 135, A550–A563 (1964).Article ADS Google Scholar Larkin, A. I. & Ovchinnikov, Y. N. Nonuniform state of superconductors. Sov. Phys. JETP 47, 1136–1146 (1964).

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Recovery of superconductivity and the critical field in layered superconductors. Phys. Rev. B 54, 1251 (1996).Article ADS Google Scholar Download referencesWe appreciate discussions with M. Feigelman. We thank Y. Guan and the Caltech Microanalysis Center for secondary-ion mass spectroscopy measurements and the Beckman Institute for their support of the X-Ray Crystallography Facility at Caltech. Funding was provided by the Air Force Office of Scientific Research (grant no. FA9550-22-1-0463 to J.F.), The Gordon and Betty Moore Foundation’s EPiQS Initiative (grant no. GBMF10638 to J.F.) and the Institute for Quantum Information and Matter, an NSF Physics Frontiers Center (grant no. PHY-2317110 to J.F.).Department of Applied Physics and Materials Science, California Institute of Technology, Pasadena, CA, USAAdrian Llanos, Veronica Show, Reiley Dorrian & Joseph FalsonInstitute for Quantum Information and Matter, California Institute of Technology, Pasadena, CA, USAAdrian Llanos, Veronica Show, Reiley Dorrian & Joseph FalsonSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarA.L. and J.F. conceived the project. A.L., V.S. and R.D. synthesized and characterized the films. A.L. and J.F. performed the low-temperature measurements. A.L. performed the fits and analysed the data. A.L. and J.F. prepared the figures. A.L. and J.F. wrote the paper with assistance from V.S. and R.D.Correspondence to Joseph Falson.The authors declare no competing interests.Nature Physics thanks Shuyuan Huyan and the other, anonymous, reviewer(s) 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.Supplementary Discussion, Figs. 1–15 and Tables 1–7.Data and fits for Fig. 1.Data and fits for Fig. 2.Data and fits for Fig. 3.Data and fits for Fig. 4.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 permissionsLlanos, A., Show, V., Dorrian, R. et al. Field-induced superconductivity in a magnetically doped two-dimensional crystal. Nat. Phys. (2026). https://doi.org/10.1038/s41567-026-03272-wDownload citationReceived: 21 February 2025Accepted: 26 March 2026Published: 23 April 2026Version of record: 23 April 2026DOI: https://doi.org/10.1038/s41567-026-03272-wAnyone 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