From oxidation state redefinition to exotic 2D magnetism: a unified picture for 1T-CrTe2.

The origin of the exciting magnetic and topological properties of the layered material 1T-CrTe2 has long been obscured by an ambiguity in its formal oxidation states. By evaluating a broad range of structural, electronic, and magnetic observables available in the literature using density functional theory (DFT) and Wannier-based analysis, our integrated computational investigation shows that 1T-CrTe2 is characterized by self-hole-doped Te 5p ligands, corresponding to a formal low-valent Cr2+/Te- electronic configuration rather than the previously assumed Cr3+/Te22- state. This unexpected Cr2+/Te1- finding provides an unprecedented, unified framework that rationalizes the existing experimental data. Our work further unveils a previously overlooked Cr 3d-Te 5p interaction, which places the anion's p-orbitals at the heart of the system's magnetism. A thorough understanding of the underlying nature of electronic and magnetic properties is essential for the design of spintronic devices and the discovery of new topological phases driven by correlated magnetism.