Dependence on pressure of conduction by hopping of small polarons in minerals of the Earth's lower mantle

摘要: Electrical conductivity of the lower mantle-like assemblage (Mg,Fe)SiO3 perovskite-(Mg,Fe)O magnesiowustite is usually analyzed using quasi-chemical Arrhenian approach diffusion. The this has often been attributed to hopping small polarons, because low value activation energy and negative volume. However, solid-state physics can provide more arguments, for or against conduction by polarons. We have tried bridge gap between two approaches identify physical quantities entering phenomenological parameters. In particular, we investigated pressure dependence energy, meaning Hopping controlled binding polaron exchange integral, which increases with causing observed decrease energy. From theory results experiments at pressures up 40 GPa temperatures 400 ∘C, estimated values parameters characteristic polarons: radius, mobility, time jumps adiabaticity. These are compatible adiabatic consequences extrapolations mantle conditions presence a temperature dependent preexponential term in expression examined. It was found that not significantly different from those Arrhenius equation.