Spin-1 Weyl Points in Isotropic Chiral Metamaterials.

We show that an isotropic medium with broken inversion symmetry can exhibit spin-1 Weyl points with a charge of 2. Such points are protected by SO(3) rotational symmetry (isotropy). We study such points in three different systems: a homogeneous chiral Lorentz medium, a periodic chiral metamaterial with point group symmetry, and a random chiral metamaterial with statistical isotropy. We further discuss how such points can be observed through reflectance and transmittance spectra. Our results demonstrate that nontrivial topology can be obtained in isotropic metamaterials, including self-assembled systems.