Fully spin-polarized hourglass charge-three Weyl points and sextuple-helicoid surface arcs in P6322 -type BaNiIO6

Magnetic topological materials exhibiting unique topological quantum physics due to the combination of spintronics and topology have aroused the interest of researchers. We propose P6322-type BaNiIO6 - a dynamically stable material with two fully spin-polarized hourglass charge-three (C-3) Weyl points (WPs) and six fully spin-polarized charge-one (C-1) WPs around the Fermi level - with the help of first-principles calculations and symmetry analysis. C-3 WPs have been theoretically proposed for more than a decade. However, they have only been reported in nonmagnetic phonon systems rather than in magnetic electronic systems. P6322-type BaNiIO6 shows 100% spin polarization and belongs to the group of half-metals due to the metallic states and the semiconducting states for the bands in spin-up and spin-down directions, respectively. The half-metallic state and the spin-polarized C-3 and C-1 WPs are robust to uniform strains (from -5 to 5%) and on-site Hubbard-Coulomb interactions (from 0 to 6 eV). Furthermore, unique surface arcs connected the projections of two spin-polarized C-3 WPs and six spin-polarized C-1 WPs, leading to fully spin-polarized sextuple-helicoid surface arcs on the (001) surface of P6322-type BaNiIO6. Undoubtedly, P6322-type BaNiIO6, with fully spin-polarized C-3 and C-1 WPs and fully spin-polarized sextuple-helicoid surface arcs, is a promising candidate for applications in spintronic and topological physics.