Metal-to-insulator transition in oxide semimetals by anion doping

Oxide semimetals exhibiting both nontrivial topological characteristics stand as exemplary parent compounds and multiple degrees of freedom, offering a promise for the realization of novel electronic states. In this work, we report the structural and transport phase transition in an oxide semimetal, SrNbO₃, achieved through effective anion doping. Notably, the resistivity increased by more than three orders of magnitude at room temperature upon nitrogen-doping. The extent of electronic modulation in SrNbO₃ is strongly correlated with misfit strain, underscoring its phase instability to both chemical doping and crystallographic symmetry variations. Using first-principles calculations, we discern that elevating the level of nitrogen doping induces an upward shift in the conductive bands of SrNbO_3−δN_δ. Consequently, a transition from a metallic state to an insulating state becomes apparent as the nitrogen concentration reaches a threshold of 1/3. This investigation shows effective anion engineering in oxide semimetals, offering pathways for manipulating their physical properties.