Robust ferromagnetism and Weyl half-semimetal in a two-dimensional vanadium boride monolayer.

Topological and ferromagnetic features in two-dimensional (2D) materials have attracted considerable interest due to their excellent physical properties. 2D Weyl half-semimetals (WHSMs) are excellent platforms to study both properties. In this study, we predicted a 2D ferromagnetic WHSM, VB28, via first-principles calculations. The VB28 monolayer displays ultra-high thermodynamic stability. It has a couple of fully spin-polarized Weyl nodal points in the spin-down channel. The Weyl points are found to be protected by vertical mirror and antiunitary C2zT symmetries, which are robust against spin-orbit coupling (SOC) and in-plane strains. Our study not only discovers an intrinsic ferromagnetic 2D WSHM material with Weyl points around the Fermi level but also provides a potential candidate with good stability for spintronic devices.