Quantum Point Contacts and Quantum Hall Interferometry on Planar Germanium

Interferometry of fractional quantum Hall states is an exciting playground for studying exotic (non-)abelian anyons. Recent works with interferometry in GaAs and graphene have demonstrated interesting statistics of odd-denominator fractions [1, 2, 3]. The interaction of integer quantum Hall states with a superconductor has also been studied, primarily with graphene [4].

Planar Germanium heterostructures, despite their outstanding semiconductor properties – high quantum mobilities, the ability to host fractional quantum Hall states [5], and high electrostatic gateability –, and their ability to be proximitised by a superconductor with a transparent interface [6], have so far been neglected in such studies involving the quantum Hall effect. Here, we will focus on Fabry-Pérot interferometers investigating integer and fractional quantum Hall states in a high-mobility 2DHG hosted in a germanium quantum well.

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[2] J. Nakamura et al.: Phys. Rev. X 13, 041012 (2023)

[3] H. K. Kundu et al.: Nat. Phys. 19, 515 (2023)

[4] H. Vignaud et al.: Nature 624, 545 (2023)

[5] D. Costa et al.: arXiv:2509.15268 (2025)

[6] L. Lakic et al.: Nat. Mater. 24, 552 (2025)