Elastic amplification from negative capacitance

TL;DR

This paper demonstrates through atomistic simulations that negative capacitance in ferroelectric heterostructures leads to an elastic amplification effect in dielectric layers, which could serve as an experimental signature and have applications in low-power actuators.

Contribution

It reveals the elastic amplification effect linked to negative capacitance in ferroelectric/dielectric superlattices using atomistic simulations, providing a new experimental fingerprint.

Findings

Enhanced elastic response in dielectric layers linked to negative capacitance

Elastic amplification correlates with voltage amplification in heterostructures

Potential application in low-power electromechanical actuators

Abstract

Ferroelectrics under suitable electric boundary conditions can present a negative capacitance response, whereby the total voltage drop across the ferroelectric opposes the externally applied bias. When the ferroelectric is in a heterostructure, this behavior yields a voltage amplification in the other elements, an effect that could be leveraged in low-power electronic devices. Interestingly, the mentioned voltage amplification should have an accompanying elastic effect. Specifically, in the typical case that the materials in contact with the ferroelectric are non-polar dielectrics, those should present an enhanced electrostrictive response. Here we use atomistic simulations - of model PbTiO$_{3}$/SrTiO$_{3}$ ferroelectric/dielectric superlattices displaying negative capacitance - to show that this is indeed the case: we reveal the enhanced elastic response of the dielectric layer and show that it is clearly linked to the voltage amplification. We argue that this "elastic amplification" could serve as a convenient experimental fingerprint for negative capacitance. Further, we propose that it may have interest on its own, e.g. for the development of low-power electromechanical actuators.