Hybrid density-functional calculation of the electronic and magnetic structures of tetragonal CuO

The electronic and magnetic properties of recently synthesized tetragonal CuO with c/a>1 is calculated by means of hybrid density-functional theory. We predict that this tetragonal phase orders antiferromagnetically and has an exceptionally high Neeacutel temperature T-N approximate to 800 K, which makes it an ideal candidate for doping experiments and a potential parent of superconductors. The electronic structure is characterized by a charge-transfer gap of 2.7 eV whereas the magnetic properties are dominated by the antiferromagnetic Cu-O-Cu interactions along the nearest-neighbor [100] direction. In addition, we predict the second tetragonal CuO phase with a c/a ratio < 1 with a different antiferromagnetic ordering and a similar high T-N. We suggest that this phase could be synthesized by epitaxial growth.