Tunable all Van der Waals Two-Dimensional Josephson Junctions

TYPECondensed Matter Seminar
Speaker:Hadar Steinberg
Affiliation:Hebrew University
Organizer:Anna Keselman
Time:14:30 - 15:30
Location:Lidow Nathan Rosen (300)

Stacked exfoliated two-dimensional materials enable the creation of diverse types of superconducting devices. I will describe a new type of superconducting two-dimensional device, where graphene forms a weak link between two ultrathin flakes of the superconductor NbSe2. Being entirely two-dimensional, these devices, which we name “two-dimensional Josephson devices” (2DJJs), have strongly suppressed orbital depairing. Added to the Ising protection of thin NbSe2, we get devices which retain their superconducting properties at very high magnetic fields applied parallel to the plane of the sample. In my talk, I will present 3 types of devices and their functionalities at high field: (i) A diffusive 2DJJ, exhibiting a pattern of suppression and recovery of superconductivity – suggestive of a 0-π transition, (ii) A ballistic 2DJJ, surviving with strong supercurrent up to 8.5 T in the plane, and (iii) A 2DJJ SQUID, where we are able to reproduce the current distribution, finding that the in-plane field induces a current re-distribution towards a narrow channel.