Magnetism and Transport in Novel High-Pressure Phases of Iron-Oxides

After the recent discovery of the high-pressure phase of Fe$_4$O$_5$, studies of the high-pressure (HP) iron oxides with unusual stoichiometries have attracted a lot of interest. These systems have a mixed-valence state of iron ions with a characteristic charge-ordering at low temperature. However, there is still a lack of knowledge for many basic properties in these systems. We study a number of compounds from the homologous series (nFeO mFe$_2$O$_3$) using Density Functional Theory (DFT) + embedded Dynamical Mean-Field Theory (eDMFT) functional method to understand the electronic structure, magnetic and transport properties. Our calculations have shown that the there is an anisotropy in the optical conductivity and the anisotropy strongly increases along the direction of the infinite chain of trigonal prism in the magnetically ordered phase of HP Fe$_3$O$_4$. Along with that we also found that there is an orbital selective Mott state in the paramagnetic phase which disappears upon magnetic ordering.