Samir Lounis
Martin-Luther-Universität Halle-Wittenberg
The phase of the quantum-mechanical wave function can encode a topological structure with wide-ranging physical consequences, such as anomalous transport effects and the existence of edge states robust against perturbations. While this has been exhaustively demonstrated for electrons, properties associated with the elementary quasiparticles in magnetic materials are still underexplored. In this talk, I will discuss our combined theoretical and experimental investigation of bulk ferromagnet Mn5Ge3, which hosts gapped topological Dirac magnons. Although inversion symmetry prohibits a net Dzyaloshinskii-Moriya interaction in the unit cell, it is locally allowed and is responsible for the gap opening in the magnon spectrum [1]. Furthermore, I will discuss the realization of topological magnon insulators in CrXTe3 (X = Si, Ge) compounds [2]. 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.
References
[1] Dos Santos Dias et al., Nature Communications 14, 7321 (2023)
[2] Zhu et al., Science Advances 7, eabi7532 (2021)