Defect-induced displacement of topological surface state in quantum magnet MnBi${}_2$Te${}_4$

Abstract

The topological magnet MnBi${}_2$Te${}_4$ (MBT), with gapped topological surface state, is an attractive platform for realizing quantum anomalous Hall and Axion insulator states. However, the experimentally observed surface state gaps fail to meet theoretical predictions, although the exact mechanism behind the gap suppression has been debated. Recent theoretical studies suggest that intrinsic antisite defects push the topological surface state away from the MBT surface, closing its gap and making it less accessible to scanning probe experiments. Here, we report on the local effect of defects on the MBT surface states and demonstrate that high defect concentrations lead to a displacement of the surface states well into the MBT crystal, validating the theorized mechanism. The local and global influence of antisite defects on the topological surface states are studied with samples of varying defect densities by combining scanning tunneling microscopy (STM), angle-resolved photoemission (ARPES), and density functional theory (DFT). Our findings identify a combination of increased defect density and reduced defect spacing as the primary factors underlying the displacement of the surface states and suppression of surface gap, guiding further development of topological quantum materials.

References in corpus (46)

• Experimental Observation of the Quantum Anomalous Hall Effect in a Magnetic Topological Insulator
• Magnetic-field-induced quantized anomalous Hall effect in intrinsic magnetic topological insulator MnBi${}_2$Te${}_4$
• Prediction and observation of the first antiferromagnetic topological insulator
• Intrinsic magnetic topological insulators in van der Waals layered MnBi${}_2$Te${}_4$-family materials
• Topological axion states in magnetic insulator MnBi${}_2$Te${}_4$ with the quantized magnetoelectric effect
• Robust axion insulator and Chern insulator phases in a two-dimensional antiferromagnetic topological insulator
• Unique thickness-dependent properties of the van der Waals interlayer antiferromagnet $\mathrm{MnB}{\mathrm{i}}_2\mathrm{T}{\mathrm{e}}_4$ films
• High-Chern-Number and High-Temperature Quantum Hall Effect without Landau Levels
• Crystal growth and magnetic structure of MnBi2Te4
• Gapless surface Dirac cone in antiferromagnetic topological insulator MnBi${}_2$Te${}_4$
• Topological Electronic Structure and Its Temperature Evolution in Antiferromagnetic Topological Insulator MnBi2Te4
• Dirac surface states in intrinsic magnetic topological insulators EuSn2As2 and MnBi2nTe3n+1
• Imaging Dirac-Mass Disorder from Magnetic Dopant-Atoms in the Ferromagnetic Topological Insulator Cr${}_x$(Bi${}_{0.1}$Sb${}_{0.9}$)${}_{2-x}$Te${}_3$
• Spin scattering and noncollinear spin structure-induced intrinsic anomalous Hall effect in antiferromagnetic topological insulator $\mathrm{MnB}{\mathrm{i}}_2\mathrm{T}{\mathrm{e}}_4$
• Gapless Dirac surface states in the antiferromagnetic topological insulator MnBi2Te4
• Evolution of structural, magnetic and transport properties in MnBi2-xSbxTe4
• Intertwined Topological and Magnetic Orders in Atomically Thin Chern Insulator MnBi2Te4
• Mn-rich MnSb2Te4: A topological insulator with magnetic gap closing at high Curie temperatures of 45-50 K
• Site Mixing for Engineering Magnetic Topological Insulators
• Electronic states and magnetic response of MnBi2Te4 by scanning tunneling microscopy and spectroscopy
• Robust A-type order and spin-flop transition on the surface of the antiferromagnetic topological insulator MnBi${}_2$Te${}_4$
• Coexistence of Surface Ferromagnetism and Gapless Topological State in MnBi${}_2$Te${}_4$
• Defect-driven ferrimagnetism and hidden magnetization in MnBi${}_2$Te${}_4$
• Magnetic topological insulator MnBi6Te10 with zero-field ferromagnetic state and gapped Dirac surface states
• Magnetic-field-induced robust zero Hall plateau state in MnBi${}_2$Te${}_4$ Chern insulator
• Tunable VUV laser based spectrometer for Angle Resolved Photoemission Spectroscopy (ARPES)
• Sample-dependent Dirac point gap in MnBi${}_2$Te${}_4$ and its response to the applied surface charge: a combined photoemission and ab initio study
• Distinct Topological Surface States on the Two Terminations of MnBi${}_4$Te${}_7$
• Universal gapless Dirac cone and tunable topological states in (MnBi${}_2$Te${}_4$)${}_m$(Bi${}_2$Te${}_3$)${}_n$ heterostructures
• Electric control of a canted-antiferromagnetic Chern insulator
• Native Defects in Antiferromagnetic Topological Insulator MnBi${}_2$Te${}_4$
• Persistent gapless surface states in MnBi2Te4/Bi2Te3 superlattice antiferromagnetic topological insulator
• Pressure-induced Topological and Structural Phase Transitions in an Antiferromagnetic Topological Insulator
• Distinct magnetic gaps between antiferromagnetic and ferromagnetic orders driven by surface defects in the topological magnet MnBi2Te4
• Hybridization-Induced Gapped and Gapless States on the Surfaces of Magnetic Topological Insulators
• Realizing gapped surface states in magnetic topological insulator MnBi${}_{2-x}$Sb${}_x$Te${}_4$
• Light-Tunable Surface State and Hybridization Gap in Magnetic Topological Insulator MnBi${}_8$Te${}_{13}$
• Visualizing the interplay of Dirac mass gap and magnetism at nanoscale in intrinsic magnetic topological insulators
• Experimental evidence on the dissipationless transport of chiral edge state of the high-field Chern insulator in MnBi2Te4 nanodevices
• Local manifestations of thickness dependent topology and axion edge state in topological magnet MnBi${}_2$Te${}_4$
• Towards the Quantized Anomalous Hall effect in AlO${}_x$-capped MnBi${}_2$Te${}_4$
• The elusive quantum anomalous Hall effect in MnBi2Te4: a materials perspective
• Detection of magnetic gap in the topological surface states of MnBi2Te4
• Even-Odd Layer-Dependent Exchange Bias Effect in MnBi2Te4 Chern Insulator Devices
• Anti-site defect-induced disorder in compensated topological magnet MnBi${}_{2-x}$Sb${}_x$Te${}_4$
• Role of Magnetic Defects and Defect-engineering of Magnetic Topological Insulators