1/B resistance oscillations within the superconducting regime of heterostructure with disordered superconductor*

In-situ growth of Al on top of shallow InAs 2DEG heterostructures gives close to perfect superconducting proximity effect [1]. In recent work, we used anodic oxidation to thin down the Al by oxidizing from the top down, allowing us to create an ultra-thin and disordered Al film with a large perpendicular critical field B_c >3 T on a mesoscopic structure. [2]
For B>B_c, the sample resistance rises to >1 kΩ whereas for B<B_c, we observe reproducible resistance oscillations of <30 Ω. The oscillations have a 1/B periodicity from which standard SdH analysis yields a density matching closely with the carrier density of the underlying 2DEG. This indicates strong electronic contact between the disordered Al layer and the high mobility InAs 2DEG, creating a novel material system to study disordered 2D superconductivity.
Furthermore, fully oxidizing the Al layer gives rise to quantum Hall effect (ρ_xx=0) emerging at B~2.5 T [2] making this material system a candidate for studying proximitized quantum Hall edge states with close to unity transparency to the superconducting Al, contacting the 2DEG from the top.

[1] M. Kjærgaard et al. Nature commun. 12841 (2016)
[2] A. C. C. Drachmann et al. work in progress (2019)