${\mathbb{Z}}_2$ Vortex Crystals in Tetrahedral Antiferromagnets: Fractional Charges and Topological Magnons

Tomoki Hirosawa, Alexander Mook, Maria Azhar

We report the formation of a ${\mathbb{Z}}_2$ vortex crystal in the tetrahedral antiferromagnetic order on a triangular lattice. The noncoplanar tetrahedral state consists of four su…