Zhu, FengfengZhang, LichuanWang, Xiaodos Santos, Flaviano JoseSong, JundaMueller, ThomasSchmalzl, KarinSchmidt, Wolfgang F.Ivanov, AlexandrePark, Jitae T.Xu, JianhuiMa, JieLounis, SamirBluegel, StefanMokrousov, YuriySu, YixiBrueckel, Thomas2021-09-252021-09-252021-09-252021-09-0110.1126/sciadv.abi7532https://infoscience.epfl.ch/handle/20.500.14299/181753WOS:000695713400030The 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 CrXTe3 (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.Multidisciplinary SciencesScience & Technology - Other Topicsmagnetismtext::journal::journal article::research article