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Published on: August 2, 2019
Al-Bi2Se3-Al Nanoribbon Josephson Junctions with Fabry-Pérot Interference: Implications for Phase-Coherent
Kiryl Niherysh1, Nermin Trnjanin1, Ananthu P Surendran1
1Quantum Device Physics Laboratory, Department of Microtechnology and Nanoscience, Chalmers University of Technology, Göteborg SE-41296, Sweden.
Abstract:
We investigate phase-coherent quantum transport in nanoscale Al-Bi2Se3-Al nanoribbon Josephson junctions by combining normal-state conductance spectroscopy with a junction-length-dependent study of Josephson transport. Differential conductance maps versus bias and gate voltage reveal Fabry-Pérot interference, whose periodicity matches the nanoribbon width, consistent with transverse quantization and quasi-ballistic surface-state trajectories in 430 nm wide devices. A systematic investigation of the characteristic voltage I c R n as a function of junction length L exhibits a clear plateau for L ≤ 500 nm, indicative of a short ballistic contribution to the Josephson transport, and decreases for longer junctions as diffusive transport dominates. Together, Fabry-Pérot interference and Josephson transport measurements provide complementary, channel-selective evidence for quasi-ballistic surface-state transport persisting over several hundred nanometers in hybrid topological insulator nanostructures. These results demonstrate the potential of Bi2Se3 nanoribbon Josephson junctions as a nanoscale platform for phase-coherent superconducting electronics, topological quantum computing architectures, and topological spintronic devices.
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