Giant nonlocal edge conduction in the axion insulator state of MnBi2Te4

Abstract

The recently discovered antiferromagnetic (AFM) topological insulator (TI) MnBi2Te4 represents a versatile material platform for exploring exotic topological quantum phenomena in nanoscale devices. It has been proposed that even-septuple-layer (even-SL) MnBi2Te4 can host helical hinge currents with unique nonlocal behavior, but experimental confirmation is still lacking. In this work, we report transport studies of exfoliated MnBi2Te4 flakes with varied thicknesses down to the few-nanometer regime. We observe giant nonlocal transport signals in even-SL devices when the system is in the axion insulator state but vanishingly small nonlocal signal in the odd-SL devices at the same magnetic field range. In conjunction with theoretical calculations, we demonstrate that the nonlocal transport is via the helical edge currents mainly distributed at the hinges between the side and top/bottom surfaces. The helical edge currents in the axion insulator state may find unique applications in topological quantum devices.

16 pages, 4 figures

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Cited by in corpus (11)

• Light-induced half-quantized Hall effect and axion insulator
• Quantum geometry quadrupole-induced third-order nonlinear transport in antiferromagnetic topological insulator MnBi2Te4
• Fabrication-induced even-odd discrepancy of magnetotransport in few-layer MnBi${}_2$Te${}_4$
• Second harmonic generation induced by gate voltage oscillation in few layer MnBi2Te4
• Dissipative Edge Transport in Disordered Axion Insulator Films
• Memristive switching in the surface of a charge-density-wave topological semimetal
• Strongly enhanced topological quantum phases in dual-surface AlO${}_x$-encapsulated MnBi${}_2$Te${}_4$
• Surface Reconstructions in Thin-Films of Magnetic Topological Insulator MnBi${}_2$Te${}_4$
• Crystalline finite-size topology
• Giant and Broadband Circular Dichroism from Particle-Hole Symmetry Breaking in Weyl Semimetals
• Giant Spin Transport Anisotropy in Magnetic Topological Insulators