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Phase interference for probing topological fractional charge in a BiSbTeSe2-based Josephson junction array.
J M Brevoord1, D H Wielens1, M Lankhorst1
1MESA+ Institute for Nanotechnology, University of Twente, The Netherlands.
Nanotechnology
|July 15, 2021
Summary
Researchers investigated fractional charges in topological insulator-superconductor interfaces. They observed phase interference in Josephson junction arrays but did not find clear evidence of axion charge effects.
Area of Science:
- Condensed Matter Physics
- Quantum Materials
- Superconductivity
Background:
- Fractional charges can arise at topological insulator (TI)-superconductor interfaces via axion electrodynamics.
- Josephson junction arrays with holes exhibit unique magnetic flux-dependent phase interference.
Purpose of the Study:
- To experimentally probe fractional charges induced by magnetic fluxes.
- To investigate phase interference effects in superconducting arrays with holes.
Main Methods:
- Fabrication and characterization of Josephson junction arrays using both gold and TI-based devices.
- Numerical simulations using the resistive shunted capacitive junction model.
- Application of magnetic fields to observe interference patterns.
Main Results:
- Observed phase interference effects in both Au- and TI-based superconducting arrays with holes.
- Experimental results showed good agreement with numerical simulations.
- No definitive evidence for axion charge-related interference was detected.
Conclusions:
- The study successfully demonstrated phase interference in superconducting arrays, validating the experimental setup.
- Further investigations are needed to identify the elusive axion charge-related interference.
- Future experiments will explore potential reasons for the lack of observed axion charge effects.
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