Revised analysis of negative capacitance in ferroelectric-insulator capacitors: analytical and numerical results, physical insight, comparison to experiments

We present a revised analysis of Negative Capacitance (NC) in ferroelectric-insulator capacitors, and particularly of the difference between systems with and without a metal interlayer. We develop a model accounting for the three-dimensional electrostatics and report analytical and numerical results based on Landau-Ginzburg equations. Our results explain the lack of NC operation in capacitors having an interlayer metal, compare well with recent experiments and enlighten the role of traps at the ferroelectric-oxide interface.