Abstract
Magnetic chains on s-wave superconductors hosting spin spirals or spin-orbit coupling may realize one-dimensional topological superconductors with Majorana modes on their edges. We study artificial spin chains, built atom-by-atom [1], with respect to such phenomena. By variation of substrate and adatom species and interatomic distances in the chain [2-5], we adjust the energies of multi-orbital Yu-Shiba Rusinov states induced by the adatoms [2,3], their hybridizations [4], as well as the chains’ spin structures [5]. This enables us to tailor the emerging multi-orbital Shiba bands such that topologically nontrivial gaps open [6] and precursors of Majorana modes appear [7]. We measure the length-dependent energy oscillations of these precursors in short chains and predict the chain length needed to drive the modes into isolated unpaired Majorana bound states [7].
We acknowledge funding by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) via the Cluster of Excellence ’Advanced Imaging of Matter’ (EXC 2056-project ID 390715994), via the SFB-925-project 170620586, and by the ERC via the Advanced Grant ADMIRE (No. 786020).
References
[1] D.-J. Choi, N. Lorente, J. Wiebe, K. von Bergmann, A. F. Otte, A. J. Heinrich, Rev. Mod. Phys. 91, (2019) 041001.
[2] L. Schneider, M. Steinbrecher L. Rózsa, J. Bouaziz, K. Palotás, M. dos Santos Dias, S. Lounis, J. Wiebe, R. Wiesendanger, npj Quantum Materials 4, (2019) 42.
[3] L. Schneider, S. Brinker, M. Steinbrecher, J. Hermenau, Th. Posske, M. dos Santos Dias, S. Lounis, R. Wiesendanger, J. Wiebe, Nature Commun. 11, (2020) 4707.
[4] P. Beck, L. Schneider, L. Rózsa, K. Palotás, A. Lászlóffy, L. Szunyogh, J. Wiebe, R. Wiesendanger, Nature Commun. 12, (2021) 2040.
[5] L. Schneider, P. Beck, J. Wiebe, R. Wiesendanger, Science Advances 7, (2021) eabd7302.
[6] L. Schneider, P. Beck, T. Posske, D. Crawford, E. Mascot, S. Rachel, R. Wiesendanger, J. Wiebe, Nat. Phys. 17 (2021) 943.
[7] L. Schneider, P. Beck, J. Neuhaus-Steinmetz, T. Posske, J. Wiebe, R. Wiesendanger, arXiv:2104.11503 [cond-mat.supr-con] (2021).
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