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4π-periodic Josephson supercurrent in HgTe-based topological Josephson junctions
J Wiedenmann1, E Bocquillon1, R S Deacon2,3
1Physikalisches Institut (EP3), Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany.
Nature Communications
|January 22, 2016
Summary
Researchers observed an anomalous Josephson effect in a HgTe weak link, revealing a 4π-periodic supercurrent contribution. This finding supports the theory of unconventional induced superconductivity in topological insulators.
Area of Science:
- Condensed Matter Physics
- Topological Materials Science
Background:
- The Josephson effect is a quantum mechanical phenomenon involving supercurrents between superconductors.
- Coupling superconductors to topological insulators is predicted to induce unconventional p-wave superconductivity.
Purpose of the Study:
- To investigate the physical nature of supercurrents in Josephson junctions involving topological insulators.
- To experimentally verify the predicted 4π-periodic Andreev bound states.
Main Methods:
- Fabrication of a Josephson junction using a HgTe weak link.
- Measurement of the junction's response to radiofrequency (rf) irradiation.
Main Results:
- Observed an anomalous response to rf irradiation, indicating a 4π-periodic supercurrent contribution.
- The amplitude of the response is consistent with theoretical predictions for gapless Andreev bound states.
Conclusions:
- The study provides experimental evidence for a 4π-periodic supercurrent in a HgTe Josephson junction.
- This work validates theoretical models of induced superconductivity in topological insulators and opens avenues for further research.
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