Unveiling negative capacitance in ferroelectric heterostructures: A 3D energy landscape perspective

Abstract

Although negative capacitance (NC) holds promise to overcome the Boltzmann tyranny, it is still subjected to debate due to the lack of a self-consistent, thermodynamic description. Herein, a 3D energy landscape is established for the ferroelectric/dielectric heterostructure, which enables precise tracking of the thermodynamic equilibria. This theoretical framework permits direct derivation of the ferroelectric component's differential capacitance, thereby provides a robust foundation for quantitative analysis of NC. Through mapping the depolarization voltage evolution and its associated energy contributions, we elucidate the underlying mechanism of the depolarization effect. Moreover, the 3D energy landscape allows for a comparative analysis of single-domain and multidomain switching pathways on the same energy scale, revealing that the former becomes energetically favorable over the latter when the series dielectric capacitance is sufficiently reduced. We also demonstrate that quasistatic NC does not necessarily ensure a dissipation-free state, challenging the conventional perspectives on the potential of NC field-effect transistors.