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Fermi-arc supercurrent oscillations in Dirac semimetal Josephson junctions
Cai-Zhen Li1,2, An-Qi Wang3, Chuan Li4
1State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing, 100871, China.
Nature Communications
|March 4, 2020
Summary
Researchers observed superconductivity in topological surface states of niobium-Dirac semimetal cadmium arsenide Josephson junctions. This finding opens possibilities for novel topological quantum devices.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Phenomena
Background:
- Topological semimetals are characterized by unique Fermi arc surface states.
- Achieving superconductivity in these Fermi arcs has been a significant challenge.
- Understanding surface state contributions to superconductivity is crucial for novel electronic applications.
Purpose of the Study:
- To investigate Fermi-arc superconductivity in a Dirac semimetal.
- To explore the behavior of supercurrents in topological surface states under magnetic fields.
- To assess the potential of Dirac semimetals for topological quantum devices.
Main Methods:
- Fabrication of niobium-Dirac semimetal cadmium arsenide-niobium Josephson junctions.
- Measurement of critical current oscillations under in-plane magnetic fields.
- Analysis of supercurrent suppression and survival in bulk versus surface states.
Main Results:
- Supercurrent from topological surface states survived magnetic fields up to 0.5 T, while bulk supercurrent was suppressed at 0.1 T.
- Fermi-arc supercurrent peaked near the Dirac point, correlating with the density of states.
- Periodic oscillations in critical current were observed with parallel magnetic fields, explained by orbital effects.
Conclusions:
- Demonstrated Fermi-arc superconductivity in a Dirac semimetal system.
- Highlighted the distinct magnetic field response of surface versus bulk superconductivity.
- Indicated that Dirac semimetal-superconductor heterostructures are promising for topological quantum technologies.
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