Critical Percolation without Fine-Tuning on the Surface of a Topological Superconductor

Phys Rev Lett. 2018 Jul 6;121(1):016802. doi: 10.1103/PhysRevLett.121.016802.

Abstract

We present numerical evidence that most two-dimensional surface states of a bulk topological superconductor (TSC) sit at an integer quantum Hall plateau transition. We study TSC surface states in class CI with quenched disorder. Low-energy (finite-energy) surface states were expected to be critically delocalized (Anderson localized). We confirm the low-energy picture, but find instead that finite-energy states are also delocalized, with universal statistics that are independent of the TSC winding number, and consistent with the spin quantum Hall plateau transition (percolation).