Weyl Metal Phase in Delafossite Oxide PtNiO${}_2$

Abstract

On the basis of density functional theory calculations we predict Weyl points in rhombohedral structure of PtNiO${}_2$ having symmorphic symmetry. From the formation energy and phonon calculations, PtNiO${}_2$ is found to be structurally stable. The magnetic ground state is ferromagnetic with an effective magnetic moment of 1.01 ${\mu }_B$ per unit cell. The electronic structure shows major contributions from Pt-$5d$, Ni-$3d$ and O-$2p$ orbitals with band crossing close to the Fermi level. The orbital contribution around 8 eV above the Fermi level are from the Pt-$s,p$ orbitals forming a kagome like electronic structure confirmed by surface Fermi surface spectral function. We found 20 pairs of confirmed Weyl nodes along the magnetic easy axis [100]. These results are expected to provide a useful and exciting platform for exploring and understanding the magnetic Weyl physics in delafossites.

14 pages, 4 figures