Pressure-induced spin transition of Fe²⁺ ion in ferropericlase from Dynamical Mean-Field Theory

The results of magnetic and spectral properties calculation for paramagnetic phase of ferropericlase (Fe$_{1/4}$Mg$_{3/4}$)O at ambient and high pressures are reported. Calculations were performed by combined Local Density Approximation + Dynamical Mean-Field Theory method (LDA+DMFT). At ambient pressure calculation gave (Fe$_{1/4}$Mg$_{3/4}$)O as insulator with Fe 3$d$-shell in high-spin state. Experimentally observed high-spin to low-spin transition of Fe$^{2+}$ ion at high pressure is successfully reproduced in calculations. Our results indicate the absence of metal-insulator transition up to the pressure 107~GPa.