Chiral Majorana Modes via Proximity to a Twisted Cuprate Bilayer

TL;DR

This paper proposes a new heterostructure combining a Rashba spin-orbit coupled substrate with a twisted cuprate bilayer under magnetic field to realize chiral topological superconductivity hosting Majorana zero modes.

Contribution

It introduces a novel heterostructure design to achieve chiral topological superconductivity with Majorana modes, leveraging the $d+id$ pairing symmetry in cuprates.

Findings

The heterostructure exhibits a nontrivial topological phase with an odd Chern number.

Majorana zero modes are predicted to appear in vortices of the system.

The system's topology is induced by the substrate and magnetic field, contrasting with isolated bilayers.

Abstract

We propose a novel heterostructure to achieve chiral topological superconductivity in 2D. A substrate with a large Rashba spin-orbit coupling energy is brought in proximity to a twisted bilayer of thin films exfoliated from a high-temperature cuprate superconductor. The combined system is then exposed to an out-of-plane magnetic field. The rare $d + id$ pairing symmetry expected to occur in such a system allows for nontrivial topology; specifically, in contrast to the case of the twisted bilayer in isolation, the substrate induces an odd Chern number. The resulting phase is characterized by the presence of a Majorana zero mode in each vortex.