Physics

Magnetic field

Acoustics

Andreev reflection

Scattering

Quantum Hall effect

Condensed matter physics

Lattice (music)

Graphene

Superconductivity

Quantum mechanics

Quantum

SciPost Physics Core

We simulate a hybrid superconductor-graphene device in the quantum Hall regime to identify the origin of downstream resistance oscillations in a recent experiment [Zhao et al., Nature Physics 16, (2020)]. In addition to the previously studied Mach-Zehnder interference between the valley-polarized edge states, we consider disorder-induced scattering, and the appearance of the counter-propagating states generated by the interface density mismatch. Comparing our results with the experiment, we conclude that the observed oscillations are induced by the interfacial disorder, and that lattice-matched superconductors are necessary to observe the alternative ballistic effects.

Mechanisms of Andreev reflection in quantum Hall graphene