Evolution of MnO under Pressure from Dynamical Mean Field Theory

Late transition metal oxides qualify as so called charge-transfer insulators whose description requires that the simple Hubbard interaction within the $3d$ orbitals has to be augmented by mixing with the ligand $2p$ states. MnO is a relatively simple realization (at ambient pressure) of such a system. Its pressure evolution at room temperature exhibits structural (B1--B8), magnetic (high spin -- low spin) and electronic (insulator -- metal) transitions, and correlated band theories$^1$ predict a S=5/2 to S=1/2 moment collapse. We report All-Electron + DMFT high-spin to low-spin or insulator to metal transitions, and a study of the paramagnetic fcc phase as volume is reduced, focusing on the behavior of the local magnetic moment and the metal-insulator transition. We also present single-particle excitation spectra that illuminate the character of the evolution.\\ $^1$D. Kasinathan et al., Phys. Rev. B {\bf 74}, 195110 (2006)