Direct evidence of ferromagnetism in a quantum anomalous Hall system

Abstract

Quantum anomalous Hall (QAH) systems are of great fundamental interest and potential application because of their dissipationless conduction without the need for external magnetic field. The QAH effect has been realized in magnetically doped topological insulator thin films. However, full quantization requires extremely low temperature ($T<50$mK) in the initial works, though it has been significantly improved with modulation doping or co-doping of magnetic elements. Improved ferromagnetism has been shown in these thin films, yet direct evidence of long-range ferromagnetic order is lacking. Herein, we present direct visualization of long-range ferromagnetic order in thin films of Cr and V co-doped (Bi,Sb)${}_2$Te${}_3$ using low-temperature magnetic force microscopy with $\text{in-situ}$ transport. The magnetization reversal process reveals typical ferromagnetic domain behavior, i.e., domain nucleation and possibly domain wall propagation, in contrast to much weaker magnetic signals observed in the end members, possibly due to superparamagnetic behavior. The observed long-range ferromagnetic order resolves one of the major challenges in QAH systems, and paves the way to high-temperature dissipationless conduction by exploring magnetic topological insulators.

arXiv commentaccepted by Nature Physics

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Cited by in corpus (46)

• Colloquium: Quantum anomalous Hall effect
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• Robust A-type order and spin-flop transition on the surface of the antiferromagnetic topological insulator MnBi${}_2$Te${}_4$
• Concurrence of Quantum Anomalous Hall and Topological Hall Effects in Magnetic Topological Insulator Sandwich Heterostructures
• Magnetic imaging of antiferromagnetic domain walls
• Record-High Proximity-Induced Anomalous Hall Effect in (Bi${}_x$Sb${}_{1-x}$)2Te${}_3$ Thin Film Grown on CrGeTe${}_3$ Substrate
• Interface-Induced Superconductivity in Magnetic Topological Insulator-Iron Chalcogenide Heterostructures
• Confinement-Induced Chiral Edge Channel Interaction in Quantum Anomalous Hall Insulators
• Direct evidence of ferromagnetism in MnSb2Te4
• Progress and prospects in the quantum anomalous Hall effect
• Zero Magnetic Field Plateau Phase Transition in Higher Chern Number Quantum Anomalous Hall Insulators
• Mesoscopic Transport of Quantum Anomalous Hall Effect in Sub-Micron Size Regime
• Conductivity of two-dimensional narrow gap semiconductors subjected to strong Coulomb disorder
• Electronic Fingerprints of Cr and V Dopants in Topological Insulator Sb2Te3
• Antiferromagnetic VdW Phase at the Interface of Sputtered Topological Insulator/Ferromagnet-Bi2Te3/Ni80Fe20 Heterostructures
• Distinct quantum anomalous Hall ground states induced by magnetic disorders
• Ferromagnetic Anomalous Hall Effect in Cr-doped Bi${}_2$Se${}_3$ Thin Films via Surface-State Engineering
• Velocity-determined anisotropic behaviors of RKKY interaction in 8-\textit{Pmmn} borophene
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• Direct observation of quantum anomalous vortex in Fe(Se,Te)
• Phase transitions in intrinsic magnetic topological insulator with high-frequency pumping
• Topological Phase Transitions Induced by Disorder in Magnetically Doped (Bi, Sb)${}_2$Te${}_3$ Thin Films
• Correlation between magnetic domain structures and quantum anomalous Hall effect in epitaxial MnBi2Te4 thin films
• Selective Control of Surface Spin Current in Topological Materials based on Pyrite-type OsX2 (X = Se, Te) Crystals
• Conductivity of two-dimensional small gap semiconductors and topological insulators in strong Coulomb disorder
• Spacer-layer-tunable magnetism and high-field topological Hall effect in topological insulator heterostructures
• Effects of Crystalline Disorder on Interfacial and Magnetic Properties of Sputtered Topological Insulator/Ferromagnet Heterostructures
• Interface Engineering Enabled Low Temperature Growth of Magnetic Insulator on Topological Insulator
• Kondo enabled transmutation between spinons and superconducting vortices: origin of magnetic memory in 4Hb-$\mathrm{Ta}{\mathrm{S}}_2$
• Mapping the phase diagram of the quantum anomalous Hall and topological Hall effects in a dual-gated magnetic topological insulator heterostructure
• Strong spin-dephasing in a topological insulator - paramagnet heterostructure
• Three-Dimensional Quantum Anomalous Hall Effect in Magnetic Topological Insulator Trilayers of Hundred-Nanometer Thickness
• From classical to quantum regime of topological surface states via defect engineering
• Chiral edge state coupling theory of transport in quantum anomalous Hall insulators
• Enhancement of temperature of quantum anomalous Hall effect in two-dimensional germanene/magnetic semiconductor heterostructures
• Distinguishing Surface and Bulk Electromagnetism via Their Dynamics in an Intrinsic Magnetic Topological Insulator
• Environmental Doping-Induced Degradation of the Quantum Anomalous Hall Insulators
• Tailoring Neel orders in Layered Topological Antiferromagnets
• Effects of GaAs buffer layer on quantum anomalous Hall insulator Vy(BixSb1-x)2-yTe3
• Interlayer Coupling-Induced Quantum Phase Transition in Quantum Anomalous Hall Multilayers
• Measured potential profile in a quantum anomalous Hall system suggests bulk-dominated current flow
• Carrier free long-range magnetism in Mo doped one quintuple layer Bi2Te3 and Sb2Te3
• Correlated disorder induced anomalous transport in magnetically doped topological insulators
• High Chern number phase in topological insulator multilayer structures: a Dirac cone model study
• Quantum anomalous Hall effect with high Chern number in two dimensional ferromagnets Ti2TeSO