Magneto-transport in Planar Graphene/d-wave Superconductor Junctions

We have recently shown experimental evidence for proximity-induced d-wave superconductivity in graphene using planar graphene/d-wave YBaCuO_7-x (YBCO) junctions, as evidenced by the conductance dependence on bias and gate voltages [1,2]. Here, we investigate the magnetic field effects on the junctions’ conductance. We find two striking effects. On the one hand, the superconducting-gap related features are progressively suppressed upon increasing the applied magnetic field, and vanish above a characteristic field in the range of 0.5-1 T. On the other hand, we find field-induced periodic oscillations of the conductance, which are only observed at energies below the superconducting gap. These oscillations are the most visible for YBCO/graphene interfaces of relatively low transparence. These findings will be discussed by considering the creation of superconducting vortices in the proximitized graphene, based on which we performed numerical simulations that can account for some of the observed behaviors.

[1] D. Perconte, et al. , Nat. Phys. 14, 25 (2018).
[2] D. Perconte, K. Seurre et al. , Phys. Rev. Lett. 125, (2020).