Role of Magnetic Defects and Defect-engineering of Magnetic Topological Insulators

Abstract

Magnetic defects play an important, but poorly understood, role in magnetic topological insulators (TIs). For example, topological surface transport and bulk magnetic properties are controlled by magnetic defects in Bi${}_2$Se${}_3$-based dilute ferromagnetic (FM) TIs and MnBi${}_2$Te${}_4$ (MBT)-based antiferromagnetic (AFM) TIs. Despite its nascent ferromagnetism, our inelastic neutron scattering data show that a fraction of the Mn defects in Sb${}_2$Te${}_3$ form strong AFM dimer singlets within a quintuple block. The AFM superexchange coupling occurs via Mn-Te-Mn linear bonds and is identical to the AFM coupling between antisite defects and the FM Mn layer in MBT, establishing common interactions in the two materials classes. We also find that the FM correlations in (Sb${}_{1-x}$Mn${}_x$)${}_2$Te${}_3$ are likely driven by magnetic defects in adjacent quintuple blocks across the van der Waals gap. In addition to providing answers to long-standing questions about the evolution of FM order in dilute TI, these results also show that the evolution of global magnetic order from AFM to FM in Sb-substituted MBT is controlled by defect engineering of the intrablock and interblock coupling.

References in corpus (28)

• Fault-tolerant quantum computation by anyons
• Anyons in an exactly solved model and beyond
• Experimental Observation of the Quantum Anomalous Hall Effect in a Magnetic Topological Insulator
• Mantid - Data Analysis and Visualization Package for Neutron Scattering and $\mu SR$ Experiments
• 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
• Experimental realization of an intrinsic magnetic topological insulator
• The development of ferromagnetism in the doped topological insulator Bi2-xMnxTe3
• Crystal growth and magnetic structure of MnBi2Te4
• A van der Waals antiferromagnetic topological insulator with weak interlayer magnetic coupling
• Intertwined Topological and Magnetic Orders in Atomically Thin Chern Insulator MnBi2Te4
• Observation of high-temperature quantum anomalous Hall regime in intrinsic MnBi${}_2$Te${}_4$/Bi${}_2$Te${}_3$ superlattice
• Competing magnetic interactions in the antiferromagnetic topological insulator MnBi${}_2$Te${}_4$
• Mn-rich MnSb2Te4: A topological insulator with magnetic gap closing at high Curie temperatures of 45-50 K
• Defect-driven ferrimagnetism and hidden magnetization in MnBi${}_2$Te${}_4$
• The Cold Neutron Chopper Spectrometer at the Spallation Neutron Source - A Review of the first 8 Years of Operation
• 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
• Electron correlation effects on exchange interactions and spin excitations in 2D van der Waals materials
• Evolution of Magnetic Interactions in Sb-substituted MnBi2Te4
• Routes to realize the axion-insulator phase in MnBi${}_2$Te${}_4$(Bi${}_2$Te${}_3$)${}_n$ family: a perspective
• Visualizing the interplay of Dirac mass gap and magnetism at nanoscale in intrinsic magnetic topological insulators
• Two-dimensional ferromagnetism with long-range interactions in the layered magnetic topological insulator MnBi2Te4
• The elusive quantum anomalous Hall effect in MnBi2Te4: a materials perspective
• Systemic Consequences of Disorder in Magnetically Self-Organized Topological MnBi${}_2$Te${}_4/$(Bi${}_2$Te${}_3$)${}_n$ Superlattices
• Two dimensional ordering and collective magnetic excitations in the dilute ferromagnetic topological insulator (Bi${}_{0.95}$Mn${}_{0.05}$)${}_2$Te${}_3$
• Localized Singlets and Ferromagnetic Fluctuations in the Dilute Magnetic Topological Insulator Sn${}_{0.95}$Mn${}_{0.05}$Te

Cited by in corpus (4)

• Atomic-Layer-Controlled Magnetic Orders in MnBi2Te4-Bi2Te3 Topological Heterostructures
• Single-layer magnet phase in intrinsic magnetic topological insulators, $[\mathrm{MnTe}][{\mathrm{Bi}}_2{\mathrm{Te}}_3{]}_{\mathrm{n}}$, far beyond the thermodynamic limit
• Synthesis of intrinsic magnetic topological insulator MnBi2nTe3n+1 family by chemical vapor transport method with feedback regulation
• Defect-induced displacement of topological surface state in quantum magnet MnBi${}_2$Te${}_4$