Density functional theory study of MnO by a hybrid functional approach

The ground state properties of MnO are investigated using the plane wave based projector augmented wave technique and the so-called ''parameter-free'' hybrid functional approach PBE0 for the approximation of the exchange-correlation energy and potential. The insulating, antiferromagnetically ordered and rhombohedrally distorted B1 structure is found to be the most stable phase of MnO, consistent with experiment. The band gap of 4.02 eV, spin magnetic moment of $4.52\phantom{\rule{0.3em}{0ex}}{\ensuremath{\mu}}_{B}$, optimized lattice parameter $a=4.40\phantom{\rule{0.3em}{0ex}}\mathrm{\AA{}}$, rhombohedral distortion angle $\ensuremath{\alpha}={0.88}^{0}$, density of states, and magnetic properties are all in good agreement with experiment. Results obtained from standard methods such as generalized gradient approximation (GGA), $\mathrm{GGA}+\mathrm{U}$ and periodic Hartee-Fock are also reported for comparative purposes. In line with previous studies, our results suggest that the applied hybrid functional method PBE0, which combines 25% of the exact exchange with a generalized-gradient approximation, corrects the deficiency of semilocal density functionals and provides an accurate quantitative description of the structural, electronic, and magnetic properties of MnO without any adjustable parameter.