Phase-coherent loops in selectively-grown topological insulator nanoribbons

• Published in: Nanotechnology Vol. 31; no. 32; p. 325001
• Main Authors: Kölzer, Jonas, Rosenbach, Daniel, Weyrich, Christian, Schmitt, Tobias W, Schleenvoigt, Michael, Jalil, Abdur Rehman, Schüffelgen, Peter, Mussler, Gregor, Sacksteder IV, Vincent E, Grützmacher, Detlev, Lüth, Hans, Schäpers, Thomas
• Format: Journal Article
• Language: English
• Published: England IOP Publishing 07.08.2020
• Subjects: nanoribbons; phase-coherent transport; selective-area growth; topological insulators; weak antilocalization
• ISSN: 0957-4484; 1361-6528
• DOI: 10.1088/1361-6528/ab898a

We succeeded in the fabrication of topological insulator (Bi0.57Sb0.43)2Te3 Hall bars as well as nanoribbons by means of selective-area growth using molecular beam epitaxy. By performing magnetotransport measurements at low temperatures information on the phase-coherence of the electrons is gained by analyzing the weak-antilocalization effect. Furthermore, from measurements on nanoribbons at different magnetic field tilt angles an angular dependence of the phase-coherence length is extracted, which is attributed to transport anisotropy and geometrical factors. For the nanoribbon structures universal conductance fluctuations were observed. By performing a Fourier transform of the fluctuation pattern a series of distinct phase-coherent closed-loop trajectories are identified. The corresponding enclosed areas can be explained in terms of nanoribbon dimensions and phase-coherence length. In addition, from measurements at different magnetic field tilt angles we can deduce that the area enclosed by the loops are predominately oriented parallel to the quintuple layers.