Topological magnon insulators in two-dimensional van der Waals ferromagnets CrSiTe<sub>3</sub> and CrGeTe<sub>3</sub>: Toward intrinsic gap-tunability.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 34516772.
- Also identified by DOI 10.1126/sciadv.abi7532 and PMC identifier 8442887.
- Licence recorded as CC BY-NC.
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Abstract
The bosonic analogs of topological insulators have been proposed in numerous theoretical works, but their experimental realization is still very rare, especially for spin systems. Recently, two-dimensional (2D) honeycomb van der Waals ferromagnets have emerged as a new platform for topological spin excitations. Here, via a comprehensive inelastic neutron scattering study and theoretical analysis of the spin-wave excitations, we report the realization of topological magnon insulators in CrXTe<sub>3</sub> (X = Si, Ge) compounds. The nontrivial nature and intrinsic tunability of the gap opening at the magnon band-crossing Dirac points are confirmed, while the emergence of the corresponding in-gap topological edge states is demonstrated theoretically. The realization of topological magnon insulators with intrinsic gap-unability in this class of remarkable 2D materials will undoubtedly lead to new and fascinating technological applications in the domain of magnonics and topological spintronics.