Effect of in-plane magnetic field on the Fraunhofer pattern in Bi₂Se₃ based Josephson junction.

We present a study of Josephson junctions based on MBE grown Bi₂Se₃ thin films contacted to superconducting aluminum electrodes. While past works have already been published on this system, we present new results that highlight the role of spin-orbit coupling on the Josephson current. On the one hand, we present a measurement of the current-phase relationship, which is found to be sinusoidal as expected for conventional Josephson junctions. On the other hand, we present, in this system, the first measurement of the Fraunhofer pattern with an in-plane magnetic field. While the Fraunhofer pattern is symmetric at zero in-plane magnetic field, it becomes asymmetric upon increasing the amplitude of the in-plane magnetic field. Theoretically, this behavior is understood as the consequence of strong spin-orbit coupling and disorder [1], a behavior that has also been observed recently with the semiconductor InAs [2].

[1] Asbjørn Rasmussen, Jeroen Danon, Henri Suominen, Fabrizio Nichele, Morten Kjaergaard, and Karsten Flensberg
Phys. Rev. B 93, 155406
[2] H. J. Suominen, J. Danon, M. Kjaergaard, K. Flensberg, J. Shabani, C. J. Palmstrøm, F. Nichele, and C. M. Marcus
Phys. Rev. B 95, 035307