Topological superconductivity in Quantum Hall-superconductor hybrid systems

TL;DR

This paper proposes a method to realize topological superconductivity with Majorana edge states in quantum Hall-superconductor hybrids by using incommensurate potentials to induce a topological phase transition.

Contribution

It introduces a new approach to engineer topological phases in QH-SC systems through potential modulation to lift degeneracies.

Findings

Incommensurate potentials can induce topological phases.

Degeneracies prevent topological phases under symmetric potentials.

Topological phases are achievable by breaking degeneracies with potential variations.

Abstract

We develop a scenario to engineer a topological phase with Majorana edge states based on an integer quantum Hall (QH) system proximity coupled to a superconductor (SC). Due to the vortices in the SC order parameter, the SC - QH hybrid system is described by a Bloch problem with ten unpaired momenta, corresponding to the maxima and saddle points of the SC order parameter. For external potentials respecting the symmetry of the vortex lattice, the states with unpaired momenta have degeneracies such that the system always is in a trivial phase. However, an incommensurate potential can lift the degeneracies and drive the system into a topologically nontrivial phase.