Spin and Orbital States in Triclinic Ilmenite-Type CuVO ₃

Ilmenite-type CuVO3 is a promising compound for exploring novel spin and orbital states, as Cu2+ (3d9) and V4+ (3d1) ions each form a honeycomb lattice. In this study, we synthesized triclinic ilmenite-type CuVO3 using a high-pressure and high-temperature method and investigated its spin and orbital states through synchrotron X-ray diffraction and measurements of electrical resistivity, magnetic susceptibility, and specific heat. The Cu2+ ions exhibit the Jahn–Teller effect, leading to the triclinic distortion. This Jahn–Teller distortion hinders the formation of static V–V dimers, in contrast to other ilmenite-type vanadium oxides in which V–V dimerization is observed. These findings highlight triclinic ilmenite-type CuVO3 as a fascinating system in which each cation exhibits characteristic spin and orbital states.