Weyl Metal Phase in Delafossite Oxide PtNiO$_2$

TL;DR

This paper predicts the existence of Weyl points in the rhombohedral structure of PtNiO$_2$, a stable, ferromagnetic delafossite oxide, revealing potential for exploring magnetic Weyl physics.

Contribution

It introduces the prediction of Weyl points in PtNiO$_2$ using density functional theory, highlighting its stability, magnetic properties, and electronic structure with Weyl nodes.

Findings

Weyl points are predicted in PtNiO$_2$ with symmorphic symmetry.

PtNiO$_2$ is structurally stable with ferromagnetic order.

20 pairs of Weyl nodes are identified along the magnetic easy axis.

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.