Exploring Quantum Hall Edge Channels in Graphene as a Path to Topological Superconductivity

Topological superconductivity has attracted considerable attention due to its great promise for fault-tolerant quantum computing. Conventional approaches rely on intricate hybrid systems combining topological insulators and superconductors, requiring precise material engineering and fine-tuned conditions, yet a clear experimental demonstration remains absent to this day. In this colloquium, I will introduce a novel type of topological insulator state emerging from the physics of the quantum Hall effect. This state leverages the unique properties of the zeroth Landau level in graphene—a remarkable, strongly interacting flat band where electron-electron interactions give rise to diverse broken-symmetry phases, characterized by distinct topological and lattice-scale orders. These phases can be identified through transport measurements [1] and directly visualized using scanning tunneling spectroscopy [2]. I will also demonstrate how superconductivity can be induced in quantum Hall edge channels to create robust Josephson junctions, despite the presence of a strong perpendicular magnetic field [3], thus opening a new path toward the realization of topological superconductivity in quantum Hall Josephson junctions.

[1] L. Veyrat et al. Science 367, 781 (2020)
[2] A. Coissard et al. Nature 605, 51 (2022)
[3] H. Vignaud et al. Nature 624, 545 (2023)