Cubic CuO: a Prototype to Study Magnetism in High-temperature Superconductors

As an exceptional member of the transition metal monoxides with a rocksalt structure, CuO exhibits a monoclinic structure and lowered Néel temperature. Since the discovery of high temperature superconductivity in the copper oxide compounds, a higher symmetry structure of CuO is highly anticipated with the highest Néel temperature among the transition metal oxides, which would be of very importance to understand the copper oxide superconductors and other correlated materials. Recently, we have grown the CuO films in a combined MBE and STM system. Both scanning transmission electron microscopy and X-ray diffraction measurements confirm the cubic rocksalt structure for CuO films. Further magnetic measurements will be performed to determine if the magnetic interactions in cubic CuO are comparable with those of high-temperature superconducting oxides.