Stabilization of negative capacitance in ferroelectric capacitors with and without a metal interlayer

The negative capacitance operation of a ferroelectric material is not only an intriguing material science topic, but also a property with important technological applications in nanoscale electron devices. Despite the growing interest for possible applications, the very existence of negative capacitance is still actively debated, even because experimental results for ferroelectric capacitors with or without a metal interlayer led to quite contradicting indications. Here we present a comprehensive analysis of the NC operation in ferroelectric capacitorsandprovidenewinsightsaboutthediscrepanciesobservedinexperiments. Our models duly account for the three-dimensional nature of the problem and show a good agreement with several aspects of recent experiments. Our results also demonstrate that traps at the ferroelectric-dielectric interface play an important role in the feasibility of a stable negative capacitance operation in ferroelectric capacitors.