Half-metallicity induced by Cr atoms on the surface of ultra-thin Cr₂Te₃film: first principles study

Non-van der Waals layered transition metal chalcogenide Cr_₂Te_₃exhibits unique properties including perpendicular magnetic anisotropy, anomalous Hall effect, and non-trivial band topology. Our first principles study further reveals that, induced by the surface Cr atoms, a transition from metallicity to a half-metallicity could occur when Cr₂Te₃is reduced to an ultra-thin film. The synergistic effect induced by the surface termination and the thickness of the film was found to play a crucial role in this transition. Specifically, a correlation between the bonding symmetry broken on the surface Cr, the strong orbital hybridization between surface Cr and Te atoms, and the squeeze of spin-down valence bands associated with Te-5porbitals below the Fermi level was found in such ultra-thin two-dimensional Cr₂Te₃film during this transition. Such a finding provides key insights into the tunability of Cr_₂Te_₃on its spintronic properties by modulating its thickness and surface termination, making it a potential application for designing high-performance spintronic devices.