Confinement-Induced Chiral Edge Channel Interaction in Quantum Anomalous Hall Insulators

Abstract

In quantum anomalous Hall (QAH) insulators, the interior is insulating but electrons can travel with zero resistance along one-dimensional conducting paths known as chiral edge channels (CECs). These CECs have been predicted to be confined to the one-dimensional (1D) edges and exponentially decay in the two-dimensional (2D) bulk. In this work, we present the results of a systematic study of QAH devices fashioned in a Hall bar geometry of different widths. At the charge neutral point, the QAH effect persists in a Hall bar device with a width of only ~72 nm, implying the intrinsic decaying length of CECs is less than ~36 nm. In the electron-doped regime, we find that the Hall resistance deviates quickly from the quantized value when the sample width is less than 1 um. Our theoretical calculations suggest that the deviation from the quantized Hall resistance in narrow QAH samples originates from the interaction between two opposite CECs mediated by disorder-induced bulk states in QAH insulators, consistent with our experimental observations.

19 pages, 5 figures, comments are welcome

References in corpus (10)

• High-precision realization of robust quantum anomalous Hall state in a hard ferromagnetic topological insulator
• Trajectory of Anomalous Hall Effect toward the Quantized State in a Ferromagnetic Topological Insulator
• Scale-Invariant Dissipationless Chiral Transport in Magnetic Topological Insulators beyond the Two-Dimensional Limit
• Giant Anisotropic Magnetoresistance in a Quantum Anomalous Hall Insulator
• Observation of the quantum-anomalous-Hall insulator to Anderson insulator quantum phase transition and its scaling behavior
• Coulomb disorder in three-dimensional Dirac systems
• Current-driven instability of quantum anomalous Hall effect in ferromagnetic topological insulators
• Charge puddles in the bulk and on the surface of the topological insulator BiSbTeSe${}_2$ studied by scanning tunneling microscopy and optical spectroscopy
• Origin of the low critical observing temperature of the quantum anomalous Hall effect in V-doped (Bi, Sb)2Te3 film
• Demonstration of Dissipative Quasihelical Edge Transport in Quantum Anomalous Hall Insulators

Cited by in corpus (16)

• Induced superconducting correlations in the quantum anomalous Hall insulator
• Light-induced phase crossovers in a quantum spin Hall system
• Cryogenic in-memory computing using magnetic topological insulators
• Theory of the microwave impedance microscopy of Chern insulators
• Proximity-induced quasi-one-dimensional superconducting quantum anomalous Hall state: a promising scalable top-down approach towards localized Majorana modes
• Macroscopic Quantum Tunneling of a Topological Ferromagnet
• Robust Majorana bound states in magnetic topological insulator nanoribbons with fragile chiral edge channels
• Characterizing the chemical potential disorder in the topological insulator (Bi${}_{1-x}$Sb${}_x$)${}_2$Te${}_3$ thin films
• Chiral edge state coupling theory of transport in quantum anomalous Hall insulators
• Dots and Boxes Algorithm for Peierls Substitution: Application to Multidomain Topological Insulators
• Optimizing proximitized magnetic topological insulator nanoribbons for Majorana bound states
• Extended Haldane Model in The Dice Lattice: Multiple Flat-Band-Induced topological Transitions Revealed
• Robust Topological Bound States in the Continuum in a Quantum Hall Bar with an Anti-dot
• Band engineering aided by topological edge state proximity effects: Inducing anti-chirality in graphene
• Designing Magnetic Topological Insulator Trilayers for Highly-Efficient Spin-Orbit Torque Switching
• Interlayer Exchange Coupling-Induced Critical-Metal-to-Insulator Phase Transition in Quantum Anomalous Hall Insulators