Joint Colloquium of CeNS, MCQST, and the LMU Faculty of Physics

Hybrid semiconductor-superconductor devices for Majorana zero modes

Prof. Georgios Katsaros | Institute for Science and Technology, Austria

Hybrid semiconductor-superconductor devices hold great promise for realizing Majorana zero modes [1-3]. However, multiple claims of Majorana detection, based on either tunnelling or Coulomb blockade (CB) spectroscopy, remain disputed. In this talk I will introduce an experimental protocol that allows to perform both types of measurement on the same hybrid island by adjusting its charging energy via tunable junctions to the normal leads [4,5]. This method reduces ambiguities of Majorana detections by checking the consistency between CB spectroscopy and zero-bias peaks in non-blockaded transport. I will discuss the theoretical interpretation of the experimental observations in terms of low-energy, longitudinally confined island states rather than overlapping Majorana modes. Finally, I will discuss about recent developments in the field, leading to "poor man's" Majoranas in minimal Kitaev chains [6].

References:
[1] Beenakker, C., Annu. Rev. of Condens. Matter Phys. 4, (2013) 113
[2] Lutchyn, R. M. et al., Nat. Rev. Mater. 3, (2018) 52
[3] Prada, E. et al., Nat. Rev. Phys. 2, (2020) 575
[4] Valentini, M. et al., Science, 373 (2021) 82
[5] Valentini M., Borovkov, M. et al., Nature 612 (2022), 442
[6] Dvir T. et al, Nature 614 (2023), 445

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