Superconducting topological devices
We engineer superconducting quantum Hall topological devices that hybridize chiral/helical edge channels with proximity superconductivity to realize and diagnose topological superconductivity. Our platform is graphene in the quantum Hall topological insulator (QHTI) regime, stabilized at low fields by metallic screening and designed for gate-tunable, spin-polarized helical edges. This single-channel control lets us study equilibration, backscattering, and Andreev processes with unprecedented precision.
On the device side, we build chiral and helical Josephson junctions in high magnetic fields, where Andreev-reflected quasiparticles inherit cyclotron chirality to form phase-coherent bound states. We integrate local gates to select and mix individual helical channels, creating well-defined chiral–helical junctions and tunable weak links. In parallel, our quantum Hall interferometry in graphene provides phase-sensitive diagnostics—probing edge coherence, path selectivity, and interaction-driven renormalization. Together, these elements establish a reproducible route to explore Majorana-compatible regimes, search for 4π-like Josephson responses, and quantify topological protection.
Methodologically, we combine ultra-clean van der Waals assembly (hBN encapsulation, metallic screening =layers), precision nanofabrication of superconducting contacts, and cryogenic measurements spanning DC transport, quantum interferometry, and microwave response. Targeted modeling and simulations guide device geometry (edge separation, gating asymmetry, contact doping) to ensure clean quantization and robust proximity.
Our goals are twofold:
- consolidate a helical, interaction-engineered platform where superconductivity and topology can be dialed with gates;
- deliver definitive, phase-sensitive tests of topological superconductivity in graphene-based hybrids—paving the way to non-Abelian modes and braiding-ready circuits.
