The interplay of superconductivity with non-trivial spin textures is promising for the engineering of non-Abelian Majorana quasiparticles. Spin–orbit coupling is crucial for the topological protection of Majorana modes as it forbids other trivial excitations at low energy but is typically intrinsic to the material1,2,3,4,5,6,7. Here, we show that coupling to a magnetic texture can induce both a strong spin–orbit coupling of 1.1 meV and a Zeeman effect in a carbon nanotube. Both of these features are revealed through oscillations of superconductivity-induced subgap states under a change in the magnetic texture. Furthermore, we find a robust zero-energy state—the hallmark of devices hosting localized Majorana modes—at zero magnetic field. Our findings are generalizable to any low-dimensional conductor, and future work could include microwave spectroscopy and braiding operations, which are at the heart of modern schemes for topological quantum computation.
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The authors declare that the main data supporting the findings of this study are available within the article (main text, methods and Supplementary information). Extra data are available from the corresponding author on reasonable request.
The codes used in this paper are available at https://github.com/Exopy.
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We are indebted to B. Leridon for the SQUID measurements and to K. Bouzehouane for MFM measurements. We acknowledge J. Palomo, M. Rosticher, A. Pierret and A. Denis for technical support. L.C.C. acknowledges the support from a Foundation CFM-J.P. Aguilar grant. The devices were made within the consortium Salle Blanche Paris Centre. This work is supported by ERC Starting Grant CIRQYS and grants from Région Ile de France and the ANR FunTheme.
The authors declare no competing interests.
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Desjardins, M.M., Contamin, L.C., Delbecq, M.R. et al. Synthetic spin–orbit interaction for Majorana devices. Nat. Mater. 18, 1060–1064 (2019). https://doi.org/10.1038/s41563-019-0457-6