Robust Majorana bound states in magnetic topological insulator nanoribbons with fragile chiral edge channels

Abstract

Magnetic topological insulators in the quantum anomalous Hall regime host ballistic chiral edge channels. When proximitized by an $s$-wave superconductor, these edge states offer the potential for realizing topological superconductivity and Majorana bound states without the detrimental effect of large externally-applied magnetic fields on superconductivity. Realizing well-separated unpaired Majorana bound states requires magnetic topological insulator ribbons with a width of the order of the transverse extent of the edge state, however, which is expected to bring the required ribbon width down to around 100 nm. In this regime, it is known to be extremely difficult to retain the ballistic nature of chiral edge channels and realize a quantized Hall conductance. In this paper, we study the impact of disorder in such magnetic topological insulator nanoribbons and compare the fragility of ballistic chiral edge channels with the stability of Majorana bound states when the ribbon is covered by a superconducting film. We find that the Majorana bound states exhibit greater robustness against disorder than the underlying chiral edge channels.

6 pages, 5 figures

References in corpus (11)

• Superconducting proximity effect and Majorana fermions at the surface of a topological insulator
• Majorana Fermions and a Topological Phase Transition in Semiconductor-Superconductor Heterostructures
• Quantized Anomalous Hall Effect in Magnetic Topological Insulators
• Imaging Dirac-Mass Disorder from Magnetic Dopant-Atoms in the Ferromagnetic Topological Insulator Cr${}_x$(Bi${}_{0.1}$Sb${}_{0.9}$)${}_{2-x}$Te${}_3$
• Estimating disorder and its adverse effects in semiconductor Majorana nanowires
• Stability of Majorana Fermions in Proximity-Coupled Topological Insulator Nanowires
• Confinement-Induced Chiral Edge Channel Interaction in Quantum Anomalous Hall Insulators
• Visualizing the interplay of Dirac mass gap and magnetism at nanoscale in intrinsic magnetic topological insulators
• Severe Dirac Mass Gap Suppression in Sb_2Te_3-based Quantum Anomalous Hall Materials
• Robust and fragile Majorana bound states in proximitized topological insulator nanoribbons
• Proximity-induced quasi-one-dimensional superconducting quantum anomalous Hall state: a promising scalable top-down approach towards localized Majorana modes

Cited by in corpus (3)

• Low-energy modeling of three-dimensional topological insulator nanostructures
• Optimizing proximitized magnetic topological insulator nanoribbons for Majorana bound states
• Controlling the magneto-transport properties of magnetic topological insulator thin films from Cr${}_x$(Bi${}_y$Sb${}_{1-y}$)${}_{2-x}$Te${}_3$ via molecular beam epitaxy