Dynamical Transition Between High-Permittivity and Low-Permittivity Oscillatory Regimes in a Ferroelectric Deep in the Ordered Phase (revised)

We report the experimental discovery of a dynamical transition between two coexisting oscillatory regimes in a bulk ferroelectric capacitor operated at room temperature, far below its Curie temperature. Following a rapid electrical excitation, the system evolves from a high-permittivity, strongly damped response to a low-permittivity, high-quality-factor underdamped oscillatory state. This spontaneous transition is controlled by the initial charging voltage and originates from the pronounced nonlinear dependence of the effective capacitance on polarization amplitude. An inertial Landau–Khalatnikov–Tani model quantitatively captures the existence of a dynamical threshold and the coexistence of multiple oscillatory attractors deep in the ordered phase. These results reveal a previously unexplored facet of ferroelectric nonlinear dynamics and suggest new opportunities for low-loss, voltage-tunable high-frequency devices.