Gate-tunable Intrinsic Anomalous Hall Effect in Epitaxial MnBi2Te4 Films

Abstract

Anomalous Hall effect (AHE) is an important transport signature revealing topological properties of magnetic materials and their spin textures. Recently, antiferromagnetic MnBi2Te4 has been demonstrated to be an intrinsic magnetic topological insulator that exhibits quantum AHE in exfoliated nanoflakes. However, its complicated AHE behaviors may offer an opportunity for the unexplored correlation between magnetism and band structure. Here, we show the Berry curvature dominated intrinsic AHE in wafer-scale MnBi2Te4 thin films. By utilizing a high-dielectric SrTiO3 as the back-gate, we unveil an ambipolar conduction and electron-hole carrier (n-p) transition in ~7 septuple layer MnBi2Te4. A quadratic relation between the saturated AHE resistance and longitudinal resistance suggests its intrinsic AHE mechanism. For ~3 septuple layer MnBi2Te4, however, the AHE reverses its sign from pristine negative to positive under the electric-gating. The first-principles calculations demonstrate that such behavior is due to the competing Berry curvature between polarized spin-minority-dominated surface states and spin-majority-dominated inner-bands. Our results shed light on the physical mechanism of the gate-tunable intrinsic AHE in MnBi2Te4 thin films and provide a feasible approach to engineering its AHE.

arXiv comment16 pages, 5 figures

References in corpus (18)

• Topological Insulators
• Anomalous Hall effect
• Wannier90: A Tool for Obtaining Maximally-Localised Wannier Functions
• Experimental Observation of the Quantum Anomalous Hall Effect in a Magnetic Topological Insulator
• Maximally localized Wannier functions: Theory and applications
• Gate-tunable Room-temperature Ferromagnetism in Two-dimensional Fe${}_3$GeTe${}_2$
• Magnetic-field-induced quantized anomalous Hall effect in intrinsic magnetic topological insulator MnBi${}_2$Te${}_4$
• Topological axion states in magnetic insulator MnBi${}_2$Te${}_4$ with the quantized magnetoelectric effect
• Anomalous Hall effect arising from noncollinear antiferromagnetism
• Experimental realization of an intrinsic magnetic topological insulator
• Semiclassical theories of the anomalous Hall effect
• Chemical Aspects of the Antiferromagnetic Topological Insulator MnBi${}_2$Te${}_4$
• Imaging Dirac-Mass Disorder from Magnetic Dopant-Atoms in the Ferromagnetic Topological Insulator Cr${}_x$(Bi${}_{0.1}$Sb${}_{0.9}$)${}_{2-x}$Te${}_3$
• Large anomalous Hall effect in ferromagnetic insulator-topological insulator heterostructures
• Dimensional Crossover Induced Topological Hall Effect in a Magnetic Topological Insulator
• Even-Odd Layer-Dependent Anomalous Hall Effect in Topological Magnet MnBi2Te4 Thin Films
• Exceptionally large anomalous Hall effect due to anticrossing of spin-split bands in the antiferromagnetic half-Heusler compound TbPtBi
• Distinct quantum anomalous Hall ground states induced by magnetic disorders

Cited by in corpus (2)

• Quantized anomalous Hall resistivity achieved in molecular beam epitaxy-grown MnBi2Te4 thin films
• Magneto-optical effects of an artificially-layered ferromagnetic topological insulator with T${}_C$ of 160 K