Berlin 2024 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 75: Low Dimensional Systems
TT 75.10: Talk
Thursday, March 21, 2024, 17:30–17:45, H 3007
Current-phase relation in Fibonacci Josephson junctions — •Ignacio Sardinero1, Jorge Cayao2, Keiji Yada3, Yukio Tanaka3, and Pablo Burset1 — 1Department of Theoretical Condensed Matter Physics, Condensed Matter Physics Center (IFIMAC) and Instituto Nicolás Cabrera, Universidad Autónoma de Madrid, 28049 Madrid, Spain — 2Department of Physics and Astronomy, Uppsala University, Box 516, S-751 20 Uppsala, Sweden — 3Department of Applied Physics, Nagoya University, Nagoya 464-8603, Japan
Quasicrystals (QCs), lattices displaying long-range order without translational periodicity, have been shown to be topologically nontrivial. They feature energy gaps linked to topological invariants, harboring edge modes under specific conditions. The Fibonacci quasicrystal (FQC), a prototypical example of a one-dimensional QC, comprises an aperiodic sequence of two alternating parameters. We consider Josephson junctions where superconductors with a finite phase difference are subjected to chemical potentials arranged in a Fibonacci sequence. The FQC arrangement, which may be implemented using local gates, introduces gaps and edge modes above the superconducting energy gap. We show that these edge modes develop superconducting correlations, with an intriguing dependence on the superconducting phase difference. This effect gives rise to a finite Josephson current which can even dominate the contribution from common Andreev states. The interplay between FQCs and the Josephson effect opens up new avenues for exploring exotic phenomena with important consequences in topological superconductivity.
Keywords: Superconductivity; Quasicrystal; Josephson effect; Andreev bound states; Topological superconductivity