Ferromagnetic-antiferromagnetic coexisting ground states and exchange bias effects in $\mathbf{MnB}{\mathbf{i}}_4\mathbf{T}{\mathbf{e}}_7$ and $\mathbf{MnB}{\mathbf{i}}_6\mathbf{T}{\mathbf{e}}_{10}$

Abstract

Natural superlattice structures $(\mathrm{MnB}{\mathrm{i}}_2\mathrm{T}{\mathrm{e}}_4)(\mathrm{B}{\mathrm{i}}_2\mathrm{T}{\mathrm{e}}_3)$${}_n$ ($n$ = 1, 2,...), in which magnetic $\mathrm{MnB}{\mathrm{i}}_2\mathrm{T}{\mathrm{e}}_4$ layers are separated by nonmagnetic $\mathrm{B}{\mathrm{i}}_2\mathrm{T}{\mathrm{e}}_3$ layers, hold band topology, magnetism and reduced interlayer coupling, providing a promising platform for the realization of exotic topological quantum states. However, their magnetism in the two-dimensional limit, which is crucial for further exploration of quantum phenomena, remains elusive. Here, complex ferromagnetic (FM)-antiferromagnetic (AFM) coexisting ground states that persist up to the 2-septuple layers (SLs) limit are observed and comprehensively investigated in $\mathrm{MnB}{\mathrm{i}}_4\mathrm{T}{\mathrm{e}}_7$ ($n$ = 1) and $\mathrm{MnB}{\mathrm{i}}_6\mathrm{T}{\mathrm{e}}_{10}$ ($n$ = 2). The ubiquitous Mn-Bi site mixing modifies or even changes the sign of the subtle inter-SL magnetic interactions, yielding a spatially inhomogeneous interlayer coupling. Further, a tunable exchange bias effect is observed in $(\mathrm{MnB}{\mathrm{i}}_2\mathrm{T}{\mathrm{e}}_4)(\mathrm{B}{\mathrm{i}}_2\mathrm{T}{\mathrm{e}}_3)$${}_n$ ($n$ = 1, 2), arising from the coupling between the FM and AFM components in the ground state. Our work highlights a new approach toward the fine-tuning of magnetism and paves the way for further study of quantum phenomena in $(\mathrm{MnB}{\mathrm{i}}_2\mathrm{T}{\mathrm{e}}_4)(\mathrm{B}{\mathrm{i}}_2\mathrm{T}{\mathrm{e}}_3)$${}_n$ ($n$ = 1, 2,...) as well as their magnetic applications.

9 pages, 4 figures

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Cited by in corpus (15)

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• Quantum geometry quadrupole-induced third-order nonlinear transport in antiferromagnetic topological insulator MnBi2Te4
• Harnessing van der Waals CrPS4 and Surface Oxides for non-monotonic pre-set field induced Exchange Bias in Fe3GeTe2
• Even-Odd Layer-Dependent Exchange Bias Effect in MnBi2Te4 Chern Insulator Devices
• Realization of Kagome Kondo lattice
• Configurable antiferromagnetic domains and lateral exchange bias in atomically thin CrPS4
• Atomic-Layer-Controlled Magnetic Orders in MnBi2Te4-Bi2Te3 Topological Heterostructures
• Symmetry-driven anisotropic coupling effect in antiferromagnetic topological insulator: Mechanism for high-Chern-number quantum anomalous Hall state
• Single-layer magnet phase in intrinsic magnetic topological insulators, $[\mathrm{MnTe}][{\mathrm{Bi}}_2{\mathrm{Te}}_3{]}_{\mathrm{n}}$, far beyond the thermodynamic limit
• Spectroscopic evidence of intra-unit-cell charge redistribution in charge-neutral magnetic topological insulator Sb-doped MnBi6Te10
• 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
• Resonantly enhanced photoemission from topological surface states in MnBi${}_6$Te${}_{10}$
• Measuring the Hall effect in hysteretic materials
• Synthesis of intrinsic magnetic topological insulator MnBi2nTe3n+1 family by chemical vapor transport method with feedback regulation