Ferroelectric superdomain switching for multi-stage negative capacitance

Abstract

Ferroelectric negative capacitance is highly promising for reducing the power consumption of ferroelectric-based devices. However, the bistable nature limits the ferroelectrics that present one negative capacitance effect during ferroelectric switching. The direct experimental creation of multi-stage negative capacitance during ferroelectric switching remains elusive thus far. Here, we have observed the novel phenomenon of twice transient negative capacitance effects occurring at unidirectional operating voltages by constructing a ferroelectric superdomain in a (111)-PbZr0.2Ti0.8O3 film. This negative capacitance can be simply operated by a unidirectional voltage, differing from the conventional operation requirements that involve alternating positive/negative voltages or complex phase transitions. Moreover, we have observed four times negative capacitance during one cycle of voltage pulse scanning. The superdomain evolution under external electric fields reveals that the switching of the superdomain undergoes an intermediate state stage, and hence, a triple-well energy landscape associated with multi-stage negative capacitance is generated during polarization switching. The observation of the multi-stage negative capacitance effect in ferroelectric films offers prospects for the design of nanoelectronics based on negative capacitance.