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HL: Fachverband Halbleiterphysik

HL 10: Focus Session: Evolution of Topological Materials into Superconducting Nanodevices I (joint session HL/TT)

HL 10.11: Vortrag

Montag, 18. März 2024, 17:45–18:00, EW 202

Transport spectroscopy on (Bi,Sb)₂Te₃ nanoribbons proximitized by aluminum as parent superconductor — •Benedikt Frohn, Tobias W. Schmitt, Vanessa S. Bello, Dennis Heffels, Albert Hertel, Michael Schleenvoigt, Abdur R. Jalil, Kristof Moors, Peter Schüffelgen, and Detlev Grützmacher — Peter Grünberg Institut, Forschungszentrum Jülich & JARA Jülich-Aachen Research Alliance, D-52425 Jülich, Deutschland

One-dimensional topological insulator nanowires which are proximitized by an s-wave superconductor and are exposed to an in-plane magnetic field are predicted to become topological superconductors [1, 2]. So far, realizing a strong proximity effect in such structures has remained an experimental challenge. In this talk, I present transport spectroscopy results on (Bi,Sb)₂Te₃ nanowires with Al as parent superconductor. All materials are grown via molecular beam epitaxy in a single growth run consisting of six subsequent deposition steps. To prevent diffusion of Al into (Bi,Sb)₂Te₃ and creating a transparent interface, we employ a thin diffusion barrier made from Pt. These devices are fabricated using stencil lithography [3] and possess contacts with varying barrier strength made of AlOx. This enables us to study the density of states and therefore to search for topological features within the induced superconducting gap, of which we measure the dependences of different magnetic field directions as well as temperature.

[1] Cook et al., Phys. Rev. B 86, 155431 (2012)

[2] Heffels et al., Nanomaterials 13, 723 (2023)

[3] Schüffelgen et al., Nat. Nanotechnology 14, 825-831 (2019)

Keywords: Topological Insulators; Superconductivity; Transport Measurements