van der Waals materials are usually characterized by a significant out-of-plane optical anisotropy, but in-plane birefringence is also necessary for photonics applications. Here, the authors report the presence of broadband optical anisotropy in a layered material, Ta2NiS5, showing in-plane birefringence of ~2 and ~0.5 in the visible and mid-infrared range, respectively.
- Yanze Feng
- Runkun Chen
- Shaojuan Li
