Symmetry-Protected Two-Dimensional Half-Semi-Metal NiVS6As2 Monolayer

Two-dimensional (2D) half-metallic magnets are expected to achieve breakthroughs in the field of spintronics and quantum computation due to their 100% spin polarization and non-dissipative ballistic transport characteristics. However, the current availability of practical applications for these materials is limited. In this paper, a new 2D material NiVS₆As₂ is predicted based on density functional theory (DFT). It has a ferromagnetic ground state with a high Curie temperature, T_C = 150 K and half-semi-metal (HSM) band structure protected by a structural symmetry degeneracy point on the Fermi surface, which can be controlled by an electric field and strain. When an out-of-plane electric field is applied, NiVS₆As₂ shows a Chern insulator with a quantum anomalous Hall (QAH) effect. These results expand the family of 2D magnetic semimetals, and provide new theoretical inspiration for understanding the protection of degenerate point symmetry.