Site Mixing for Engineering Magnetic Topological Insulators

Abstract

The van der Waals compound, MnBi${}_2$Te${}_4$, is the first intrinsic magnetic topological insulator, providing a materials platform for exploring exotic quantum phenomena such as the axion insulator state and the quantum anomalous Hall effect. However, intrinsic structural imperfections lead to bulk conductivity, and the roles of magnetic defects are still unknown. With higher concentrations of same types of magnetic defects, the isostructural compound MnSb${}_2$Te${}_4$ is a better model system for a systematic investigation of the connections among magnetic, topology and lattice defects. In this work, the impact of antisite defects on the magnetism and electronic structure is studied in MnSb${}_2$Te${}_4$. Mn-Sb site mixing leads to complex magnetic structures and tunes the interlayer magnetic coupling between antiferromagnetic and ferromagnetic. The detailed nonstoichiometry and site-mixing of MnSb${}_2$Te${}_4$ crystals depend on the growth parameters, which can lead to $\approx$40\% of Mn sites occupied by Sb and $\approx$15\% of Sb sites by Mn in as-grown crystals. Single crystal neutron diffraction and electron microscopy studies show nearly random distribution of the antisite defects. Band structure calculations suggest that the Mn-Sb site-mixing favors a FM interlayer coupling, consistent with experimental observation, but is detrimental to the band inversion required for a nontrivial topology. Our results suggest a long range magnetic order of Mn ions sitting on Bi sites in MnBi${}_2$Te${}_4$. The effects of site mixing should be considered in all layered heterostructures that consist of alternating magnetic and topological layers, including the entire family of MnTe(Bi${}_2$Te${}_3$)${}_n$, its Sb analogs and their solid solution.

The effects of Mn/Sb antisite mixing on the magnetic structure (experiment) and band topology (theory) in the van der Waals magnet MnSb${}_2$Te${}_4$. PRX in press

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Cited by in corpus (41)

• Colloquium: Quantum anomalous Hall effect
• Defect-driven ferrimagnetism and hidden magnetization in MnBi${}_2$Te${}_4$
• Evolution of Magnetic Interactions in Sb-substituted MnBi2Te4
• Ferromagnetic-antiferromagnetic coexisting ground states and exchange bias effects in $\mathbf{MnB}{\mathbf{i}}_4\mathbf{T}{\mathbf{e}}_7$ and $\mathbf{MnB}{\mathbf{i}}_6\mathbf{T}{\mathbf{e}}_{10}$
• Evidence for a magnetic-field induced ideal type-II Weyl state in antiferromagnetic topological insulator Mn(Bi1-xSbx)2Te4
• Tuning the magnetism and band topology through antisite defects in Sb doped MnBi4Te7
• Routes to realize the axion-insulator phase in MnBi${}_2$Te${}_4$(Bi${}_2$Te${}_3$)${}_n$ family: a perspective
• Pressure-tuned intralayer exchange in superlattice-like MnBi2Te4/(Bi2Te3)n topological insulators
• Distinct magnetic gaps between antiferromagnetic and ferromagnetic orders driven by surface defects in the topological magnet MnBi2Te4
• Visualizing the interplay of Dirac mass gap and magnetism at nanoscale in intrinsic magnetic topological insulators
• Growth, characterization and Chern insulator state in MnBi${}_2$Te${}_4$ via the chemical vapor transport method
• Coexistence of Ferromagnetism and Topology by Charge Carrier Engineering in intrinsic magnetic topological insulator MnBi4Te7
• Delicate Ferromagnetism in MnBi${}_6$Te${}_{10}$
• Magnetic dilution effect and topological phase transitions in (Mn${}_{1-x}$Pb${}_x$)Bi${}_2$Te${}_4$
• Approaching a Minimal Topological Electronic Structure in Antiferromagnetic Topological Insulator MnBi2Te4 via Surface Modification
• The elusive quantum anomalous Hall effect in MnBi2Te4: a materials perspective
• Towards the Quantized Anomalous Hall effect in AlO${}_x$-capped MnBi${}_2$Te${}_4$
• Ferromagnetic MnBi4Te7 obtained with low concentration Sb doping: A promising platform for exploring topological quantum states
• Intrinsic magnetic topological insulators of the MnBi${}_2$Te${}_4$ family
• Fabrication-induced even-odd discrepancy of magnetotransport in few-layer MnBi${}_2$Te${}_4$
• Systemic Consequences of Disorder in Magnetically Self-Organized Topological MnBi${}_2$Te${}_4/$(Bi${}_2$Te${}_3$)${}_n$ Superlattices
• On the topological surface states of the intrinsic magnetic topological insulator Mn-Bi-Te family
• Unconventional pressure-driven metamagnetic transitions in topological van der Waals magnets
• Anti-site defect-induced disorder in compensated topological magnet MnBi${}_{2-x}$Sb${}_x$Te${}_4$
• Ferroelectrically switchable magnetic multistates in MnBi${}_2$Te${}_4$(Bi${}_2$Te${}_3$)${}_n$ and MnSb${}_2$Te${}_4$(Sb${}_2$Te${}_3$)${}_n$ (n = 0, 1) thin films
• Momentum-inversion symmetry breaking on the Fermi surface of magnetic topological insulators
• Unusual dynamic susceptibility arising from soft ferromagnetic domains in MnBi8Te13 and Sb-doped MnBi2nTe3n+1 (n=2, 3)
• Superconductivity by alloying the topological insulator SnBi2Te4
• Non-volatile Electric Control of Magnetic and Topological Properties of MnBi2Te4 Thin Films
• Atomic-Layer-Controlled Magnetic Orders in MnBi2Te4-Bi2Te3 Topological Heterostructures
• Topological surface currents accessed through reversible hydrogenation of the three-dimensional bulk
• Quantum Effects at a Spin-Flop Transition in the Antiferromagnetic Topological Insulator MnBi${}_2$Te${}_4$
• Hall-effect in the MnBi_2Te_4 crystal using silicon nitride nanomembrane via contacts
• Fermi level dependence of magnetism and magnetotransport in the magnetic topological insulators Bi${}_2$Te${}_3$ and BiSbTe${}_3$ containing self-organized MnBi${}_2$Te${}_4$ septuple layers
• Single-layer magnet phase in intrinsic magnetic topological insulators, $[\mathrm{MnTe}][{\mathrm{Bi}}_2{\mathrm{Te}}_3{]}_{\mathrm{n}}$, far beyond the thermodynamic limit
• Optical study of the charge dynamics evolution in the topological insulators MnBi${}_2$Te${}_4$ and Mn(Bi${}_{0.74}$Sb${}_{0.26}$)${}_2$Te${}_4$ under high pressure
• Evolution of the optical response of the magnetic topological insulators Mn(Bi${}_{1-x}$Sb${}_x$)${}_2$Te${}_4$ with Sb content
• Relationship among Structural, Disordered, Magnetism and Band Topology in MnSb2Te4(Sb2Te3)n Family
• Interplay between surface Dirac and Rashba states specific for topologically nontrivial van der Waals superlattices
• Defect-induced displacement of topological surface state in quantum magnet MnBi${}_2$Te${}_4$
• Light-driven topological and magnetic phase transitions in thin-layer antiferromagnets