Influence of molecular orbitals on magnetic properties of FeO2HX

Recent discoveries of various novel iron oxides and hydrides, which become stable at very high pressure and temperature, are extremely important for geoscience. In this paper, we report the results of an investigation on the electronic structure and magnetic properties of the hydride FeO2Hx, using density functional theory plus dynamical mean-field theory (DFT+DMFT) calculations. An increase in the hydrogen concentration resulted in the destruction of dimeric oxygen pairs and, hence, a specific band structure of FeO2 with strongly hybridized Fe-t2g-O-pz anti-bonding molecular orbitals, which led to a metallic state with the Fe ions at nearly 3+. Increasing the H concentration resulted in effective mass enhancement growth which indicated an increase in the magnetic moment localization. The calculated static momentum-resolved spin susceptibility demonstrated that an incommensurate antiferromagnetic (AFM) order was expected for FeO2, whereas strong ferromagnetic (FM) fluctuations were observed for FeO2H. © 2020 by the authors.Russian Science Foundation, RSF: 19-72-30043Funding: The DFT+DMFT calculations were supported by the Russian Science Foundation (Project No. 19-72-30043). The calculations of static momentum-resolved spin susceptibility were performed within the state assignment of Minobrnauki of Russia (theme “Quantum” No. AAAA-A18-118020190095-4), act 11 contract 02.A03.21.00006 and project RFBR 20-32-70019