Interlayer current near the edge of an $\mathrm{InAs/GaSb}$ double quantum well in proximity with a superconductor

We investigate charge transport through the junction between a niobium superconductor and the edge of a two-dimensional electron-hole bilayer, realized in an $\mathrm{InAs/GaSb}$ double quantum well. For the transparent interface with a superconductor, we demonstrate that the junction resistance is determined by the interlayer charge transfer near the interface. From an analysis of experimental $I$–$V$ curves, we conclude that the proximity-induced superconductivity efficiently couples electron and hole layers at low currents. The critical current demonstrates periodic dependence on the in-plane magnetic field, while it is monotonic for the field that is normal to the bilayer plane.