Thermodynamic driving force of transient negative capacitance of ferroelectric capacitors

TL;DR

This paper clarifies the thermodynamic origin of transient negative capacitance in ferroelectric capacitors, showing it is driven by energy barrier disappearance rather than negative curvature of the energy landscape.

Contribution

It reveals that the transient negative capacitance arises from the energy barrier disappearance, challenging the traditional Landau-Khalatnikov theory and incorporating both material and circuit factors.

Findings

Transient NC is driven by the minimum of elastic Gibbs free energy minus polarization work.

The phenomenon occurs when the energy barrier of the elastic Gibbs free energy landscape disappears.

Transient NC depends on both material parameters and circuit conditions.

Abstract

This paper investigates the thermodynamic driving force of transient negative capacitance (NC) in the series circuit of the resistor and ferroelectric capacitor (R-FEC). We find that the widely used Landau-Khalatnikov (L-K) theory, that is, the minimum of the Gibbs free energy, is inapplicable to explain the transient NC. The thermodynamic driving force of the transient NC phenomenon is the minimum of the difference between the elastic Gibbs free energy and the electric polarization work. The appearance of the transient NC phenomenon is not due to the widely accepted view that the ferroelectric polarization goes through the negative curvature region of elastic Gibbs free energy landscape (Ga). Instead, the transient NC phenomenon appears when the energy barrier of Ga disappears. The transient NC is dependent on both the intrinsic ferroelectric material parameters and extrinsic factors in the R-FEC circuit.