Phase-coherent loops in selectively-grown topological insulator nanoribbons

Abstract

Universal conductance fluctuations and the weak antilocalization effect are defect structure specific fingerprints in the magnetoconductance that are caused by electron interference. Experimental evidence is presented that the conductance fluctuations in the present topological insulator (Bi${}_{0.57}$Sb${}_{0.43}$)${}_2$Te${}_3$ nanoribbons which are selectively grown by molecular beam epitaxy are caused by well-defined and sharply resolved phase-coherent loops. From measurements at different magnetic field tilt angles we deduced that these loops are preferentially oriented parallel to the quintuple layers of the topological insulator material. Both from a theoretical analysis of universal conductance fluctuations and from weak antilocalization measured at low temperature the electronic phase-coherence lengths $l_{\varphi }$ are extracted, which is found to be larger in the former case. Possible reasons for this deviation are discussed.

7 pages, 6 figure

References in corpus (9)

• Gate-Voltage Control of Chemical Potential and Weak Anti-localization in Bismuth Selenide
• Coexistence of the topological state and a two-dimensional electron gas on the surface of Bi2Se3
• Impurity effect on weak anti-localization in the topological insulator Bi2Te3
• Tunable Surface Conductivity in Bi2Se3 Revealed in Diffusive Electron Transport
• Aharonov-Bohm oscillations in disordered topological insulator nanowires
• Anomalous Aharonov-Bohm conductance oscillations from topological insulator surface states
• Transport Properties of Topological Insulators: Band Bending, Bulk Metal-to-Insulator Transition, and Weak Anti-Localization
• Resolving the Dirac Cone on the Surface of Bi2Te3 Topological Insulator Nanowires by Field-Effect Measurements
• Topological Effects on the Magnetoconductivity in Topological Insulators