Quantum anomalous Hall effect and topological superconductivity in nanoscale magnetic topological insulators with spatially-correlated disorder

Magnetically-doped 3D topological insulators in the quantum anomalous Hall phase can host ballistic chiral edge channels. When proximitised by an s-wave superconductor, these edge states realise a topological superconductor with Majorana zero modes (MZMs), in principle without the need for large externally-applied magnetic fields. Realising MZMs, however, requires nanoscale structures of the order of the superconducting coherence length where edge states can percolate via the bulk. In this work we use tight-binding simulations to study this trade off between the breakdown of the quantum anomalous Hall phase and the Andreev coupling required for MZMs in the presence of realistic spatially-correlated electrostatic and magnetic disorder.