Quantum Transport in Topological Surface States of Selectively Grown Bi<sub>2</sub>Te<sub>3</sub> Nanoribbons
Daniel Rosenbach, Nico Oellers, Abdur Rehman Jalil, Martin Mikulics, Jonas Kölzer, Erik Zimmermann, Gregor Mussler, Stephany Bunte, Detlev Grützmacher, Hans Lüth, Thomas Schäpers
Abstract
Abstract Quasi‐1D nanowires of topological insulators are candidate structures in superconductor hybrid architectures for Majorana fermion based quantum computation schemes. Here, selectively grown Bi 2 Te 3 topological insulator nanoribbons at cryogenic temperatures are investigated. The nanoribbons are defined in deep‐etched Si 3 N 4 /SiO 2 nano‐trenches on a silicon (111) substrate followed by a selective area growth process via molecular beam epitaxy. The selective area growth is beneficial to the device quality, as no subsequent fabrication needs to be performed to shape the nanoribbons. In the diffusive transport regime of these unintentionally n ‐doped Bi 2 Te 3 topological insulator nanoribbons, electron trajectories are identified by analyzing angle dependent universal conductance fluctuation spectra. When the sample is tilted from a perpendicular to a parallel magnetic field orientation, these high frequent conductance modulations merge with low frequent Aharonov–Bohm type oscillations originating from the topologically protected surface states along the nanoribbon perimeter. For 500 nm wide Hall bars low frequent Shubnikov–de Haas oscillations are identified in a perpendicular magnetic field orientation. These reveal a topological, high‐mobility, 2D transport channel, partially decoupled from the bulk of the material.