On the applicability of Gibbs free energy landscape to the definition and understanding of transient negative capacitance in a ferroelectric capacitor

We investigate the applicability of the Gibbs free energy landscape to the definition and understanding of transient negative capacitance in a ferroelectric capacitor. We find that the Gibbs free energy cannot define the transient negative capacitance. In order to define the negative capacitance, we suggest returning to the original definition of capacitance, which is the second-order derivative of electrostatic force work with respect to polarization.