Delicate Ferromagnetism in MnBi${}_6$Te${}_{10}$

Abstract

Tailoring magnetic orders in topological insulators is critical to the realization of topological quantum phenomena. An outstanding challenge is to find a material where atomic defects lead to tunable magnetic orders while maintaining a nontrivial topology. Here, by combining magnetization measurements, angle-resolved photoemission spectroscopy, and transmission electron microscopy, we reveal disorder-enabled, tunable magnetic ground states in MnBi${}_6$Te${}_{10}$. In the ferromagnetic phase, an energy gap of 15 meV is resolved at the Dirac point on the MnBi${}_2$Te${}_4$ termination. In contrast, antiferromagnetic MnBi${}_6$Te${}_{10}$ exhibits gapless topological surface states on all terminations. Transmission electron microscopy and magnetization measurements reveal substantial Mn vacancies and Mn migration in ferromagnetic MnBi${}_6$Te${}_{10}$. We provide a conceptual framework where a cooperative interplay of these defects drives a delicate change of overall magnetic ground state energies, and leads to tunable magnetic topological orders. Our work provides a clear pathway for nanoscale defect-engineering towards the realization of topological quantum phases.

22 pages, 3 figures

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Cited by in corpus (10)

• Intrinsic magnetic topological insulators of the MnBi${}_2$Te${}_4$ family
• Ubiquitous order-disorder transition in the Mn antisite sublattice of the (MnBi${}_2$Te${}_4$)(Bi${}_2$Te${}_3$)${}_n$ magnetic topological insulators
• 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
• Magneto-optical effects of an artificially-layered ferromagnetic topological insulator with T${}_C$ of 160 K
• 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
• Self-organization mechanism in Bridgman-grown MnBi2Te4/(Bi2Te3)n: influence on layer sequence and magnetic properties
• Resonantly enhanced photoemission from topological surface states in MnBi${}_6$Te${}_{10}$
• Synthesis of intrinsic magnetic topological insulator MnBi2nTe3n+1 family by chemical vapor transport method with feedback regulation