Switching dynamics and transient negative capacitance in improper ferroelectric h-YbFeO₃ film

The transient negative capacitance (NC) effect in ferroelectric thin film, serving as the touchstone for the nature of transient polarization states and related ferroelectric switching dynamics, has received wide attentions. To date, all known NC effects are limited to proper ferroelectrics, limiting the general applicability and interpretation of NC in ferroelectric materials. In this work, we report, for the first time, the transient NC effects and the underlying switching dynamics in improper ferroelectric h-YbFeO₃ films. The transient NC range was dominated by inhomogeneous nucleation and the subsequent concave trend of electric responses imply the effect of negative curvature of energy potential, providing the reconciliation to the existing controversy for the physical origins of transient NC. The processes including transient NC are simulated with high consistency basing on phenomenological theory of switching dynamics. The frequency-dependent effective modulation of transient NC reveals the dominant role of initial multidomain states, providing the insights for controlling transient NC effects beyond extrinsic factors.