Date/Time
Date(s) - 26/11/2025
10:30 am - 11:30 am

BSB 108

Dr. Biao Lian
Assistant Professor
Princeton University

Profile: https://phy.princeton.edu/people/biao-lian

TITLE: Reconstructing topological edge states with superconductivity

ABSTRACT:

Insulating topological phases in two-dimensions such as the quantum Hall states can have metallic topological edge states, which give rise to resistances taking quantized values. In recent years, there has been growing experimental interests in studying quantum Hall edge states in proximity to a superconductor (SC); however, a quantized resistance signature is usually lacking, due to the non-universal superconducting couplings and unavoidable disorders. We demonstrate that a novel quantized resistance can be realized for certain fractional quantum Hall (FQH) edge states with disordered SC proximity. The example I will show is the filling 2/3 FQH state, which is known to have a pair of counter-propagating edge modes. We predict that disordered SC-couplings can reconstruct the edge modes into an infinite set of stable phases with quantized electron-to-hole conversion probability, which gives rise to a quantized downstream resistance in the FQH-SC junction. This provides a quantized electrical transport signature for the SC-reconstructed phase of edge states, which is beyond the quantized Hall resistance. Our results reveal a rich landscape of disorder-stabilized phases in topological edge states with SC proximity.