Voltage Dependent Viscosity in Landau-Khalatnikov Theory for Switching Dynamics

In this work, we elaborate a deficiency of the single domain Landau-Khalatnikov (LK) equation for the ferroelectric switching. Agreements between LK with the Kolmogorov-Avrami-Ishibashi (KAI) model are observed. However, a voltage dependence of the time constant is revealed due to the capacitance non-linearity beyond the coercive voltage, although it resembles the trend of Merz’s law. Experimental data show that electric field controls the switching time, following a nucleation limiting switch scenario. As a result, the voltage dependence of the viscosity parameter is necessary for the switch dynamics of widely used ferroelectric materials.