Freiburg 2019 – scientific programme

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FM: Fall Meeting

FM 63: Poster: Enabling Technologies: Quantum Materials, Quantum Dots, Quantum Wires, Point Contacts and Superconducting Systems

FM 63.23: Poster

Wednesday, September 25, 2019, 16:30–18:30, Tents

Selective area growth of topological insulator nanowires by molecular beam epitaxy — •Andrea Bliesener¹, Gertjan Lippertz^1,2, Oliver Breunig¹, Alexey Taskin¹, and Yoichi Ando¹ — ¹Institute of Physics II, University of Cologne, Germany — ²Instituut voor Kern- en Stralingsfysica, KU Leuven, Belgium

Inducing superconductivity into a topological insulator nanowire by proximitizing it with an s-wave superconductor is predicted to give rise to Majorana bound states. [1] This strategy promises a more robust alternative to the conventional semiconductor approach.
To realize this platform, we grow Si₃N₄ on a sapphire substrate and pattern it by electron-beam lithography into nanowire devices. We use this pre-patterned substrate to selectively grow topological insulator nanowires by molecular beam epitaxy. Control of the chemical potential is achieved by a side-gate, alleviating the need for additional fabrication steps after growth. The nanowires are characterized using magneto-transport measurements.
Here we show our first results towards growing bulk insulating (Bi_1−xSb_x)₂Te₃ (BST) nanowires which have widths below 100nm. Optimizing the composition between n-type Bi₂Te₃ and p-type Sb₂Te₃ can give almost perfect compensation of charge carriers in BST.
[1] L. Fu and C.L. Kane, Phys. Rev. Lett. 100, 096407 (2008)