Structure, phase stability, half-metallicity, and fully spin-polarized Weyl states in compound NaV2O4: a new example for topological spintronic material

TL;DR

This paper predicts that NaV2O4 is a stable, half-metallic topological spintronic material with fully spin-polarized Weyl states and robust nodal lines, promising for advanced spintronic applications.

Contribution

It introduces NaV2O4 as a new topological spintronic material with unique fully spin-polarized Weyl and nodal line states, expanding the class of materials for spintronics.

Findings

NaV2O4 has a tetragonal, stable structure.

It exhibits a half-metallic ground state with spin-up bands near Fermi level.

The Weyl nodal line is robust and fully spin-polarized, with clear drumhead surface states.

Abstract

Here, we systematically investigate the structure, phase stability, half-metallicity, and topological electronic structure for a new topological spintronic material NaV2O4. The material has a tetragonal structure with excellent dynamical and thermal stabilities. It shows a half-metallic ground state, where only the spin-up bands present near the Fermi level. These bands form a Weyl nodal line close to the Fermi level, locating in the kz = 0 plane. The nodal line is robust against SOC, under the protection of the mirror symmetry. The nodal line band structure is very clean, thus the drumhead surface states can be clearly identified. Remarkably, the nodal line and drumhead surface states have the 100% spin polarization, which are highly desirable for spintronics applications. In addition, by shifting the magnetic field in-plane, we find that the Weyl nodal line can transform into single pair of Weyl nodes. The Weyl-line and Weyl-node fermions in the bulk, as well as the drumhead fermions on the surface are all fully spin-polarized, which may generate new physical properties and promising applications.