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.