Helical superconducting edge modes from pseudo-Landau levels in graphene

TL;DR

This paper investigates topologically protected helical edge modes in graphene induced by pseudo-Landau levels under strain and magnetic fields, proposing an experimental setup to observe these gapless states.

Contribution

It demonstrates the emergence of gapless helical modes at the zeroth pseudo-Landau level in strained graphene-superconductor interfaces, revealing a new topological transition.

Findings

Identification of a topological transition near the zeroth pseudo-Landau level

Prediction of a protected helical mode at the interface

Proposal for experimental detection using strained suspended membranes

Abstract

We explore Andreev states at the interface of graphene and a superconductor for a uniform pseudo-magnetic field. Near the zeroth-pseudo Landau level, we find a topological transition as a function of applied Zeeman field, at which a gapless helical mode appears. This 1D mode is protected from backscattering as long as intervalley- and spin-flip scattering are suppressed. We discuss a possible experimental platform to detect this gapless mode based on strained suspended membranes on a superconductor, in which dynamical strain causes charge pumping