Josephson junctions

In recent years 2D materials like WSe₂ are utilised to induce spin-orbit interaction in bilayer graphene (BLG), which can even lead to topological band-inverted phase in a symmetrically WSe₂ encapsulated BLG [6]. Here, we investigate the supercurrent in WSe₂/BLG/ WSe₂ Josephson junctions close to band-inverted regime by dual gate tuning of carrier density and displacement field (D). Along the charge neutrality line, we observe a suppression of supercurrent at D=0 indicative of band-inversion. In the absence of in-plane magnetic field, the current-phase relation (CPR) extracted from quantum interferometry measurement shows no phase shift as expected. However the application of field results in anomalous CPR with finite phase shift which is pronounced for p-doped regime with higher junction transparency. Our work opens novel possibilities for phase-controlled Josephson junctions as well as topological superconductivity in Van der Waals materials with spin-orbit coupling.

[1] J. O. Island, X. Cui, C. Lewandowski, J. Y. Khoo, E. M. Spanton, H. Zhou, D. Rhodes, J. C. Hone, T. Taniguchi, K. Watanabe, L. S. Levitov, M. P. Zaletel, and A. F. Young, Nature 571, 85 (2019).