Ferroelectrics, Negative Capacitance and Depolarization Field: What exactly is negative capacitance?

Abstract

2019 marks the 11th year since the concept of ferroelectric negative capacitance was first proposed [1]. It was proposed as a physics solution to an engineering problem: The power dissipation in electronics and computing. Yet, it was unique in that the technology required a fundamental scientific discovery in a field that was ~90 years old at that time-the discovery of negative capacitance or static negative permittivity in ferroelectrics. Initially, interests into negative capacitance were limited to the device researchers; over time, the topic brought together the “often-disjoint” communities of device engineers, condensed matter physicists and material scientists in exploring, understanding and finally discovering this phenomenon [2]–[7]. Different manifestations of the negative capacitance phenomenon, namely, capacitance enhancement, negative differential relation between charge and voltage as well as atomic scale mapping of the stabilized, negative capacitance states corroborated with phase field and density functional theory based calculations have established this concept on a solid ground.