Spin-Orbit-Enhanced Robustness of Supercurrent in Graphene/WS_{2} Josephson Junctions

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Electronics

Background:

• Supercurrents in graphene-based Josephson junctions are crucial for quantum electronics.
• Inducing strong spin-orbit interactions (SOIs) is a key strategy to enhance superconducting properties.
• Comparing different substrate materials is essential to understand their influence on induced SOIs.

Purpose of the Study:

• To demonstrate enhanced supercurrent robustness in graphene Josephson junctions with induced SOIs.
• To compare the performance of graphene on hexagonal boron-nitride (hBN) versus graphene on WS_{2} under high magnetic fields.
• To investigate the role of WS_{2} in stabilizing superconducting states via SOIs.

Main Methods:

• Fabrication of graphene-based Josephson junctions on hBN and WS_{2} substrates.
• Measurement of supercurrent persistence in high out-of-plane magnetic fields.
• Analysis of differential resistance to identify signatures of induced superconductivity.

Main Results:

• Both graphene/hBN and graphene/WS_{2} junctions show induced superconductivity up to 1 T in short devices.
• Longer graphene/WS_{2} junctions exhibit robust induced superconductivity persisting up to 7 T.
• Graphene/hBN junctions show suppressed superconducting signatures at lower magnetic fields.

Conclusions:

• Strong SOIs induced by WS_{2} significantly enhance the robustness of supercurrents in graphene Josephson junctions.
• Quasiballistic edge states, stabilized by SOIs, are responsible for the observed robust superconductivity in graphene/WS_{2}.
• Graphene/WS_{2} heterostructures offer a promising platform for developing advanced superconducting quantum devices.