Current-phase relation of a short multi-mode Bi₂Se₃ topological insulator nanoribbon Josephson junction with ballistic transport modes

Abstract We used the asymmetric superconducting quantum interference device (SQUID) technique to extract current phase relation (CPR) of a Josephson junction with 3D-topological insulator (3D-TI) Bi 2 Se 3 nanobelt as barrier. The obtained CPR shows deviations from standard sinusoidal pronounced forward skewness. At temperatures below 200 mK, skewness values are above zero temperature limit for short diffusive junctions. Fitting extracted that most supercurrent is carried by ballistic topological surface states (TSSs), small contribution channels primarily due bulk. These findings instrumental in engineering devices can fully exploit properties topologically protected 3D TIs.