摘要

Condensed matter system have now became a fertile ground to study emerging topological quasi-particles with symmetry protected edge mode. While extensive studies are focused on Fermionic excitations, the same conceptual framework can also be applied to Bosonic systems and yield new types of topological states. In the talk, I will show our recent inelastic x-ray scattering study of transition metal monosilicide. By directly map out the phonon band structure, we discovered the double-Weyl points, which have not been observed in electronic systems. Our study thus provides transition metal monosilicides as ideal platform to explore emerging Bosonic excitations and its topological non-trivial edge modes.