Authors: Qiwu Shi, Eric Parsonnet, Xiaoxing Cheng, Natalya Fedorova, Ren-Ci Peng, Abel Fernandez, Alexander Qualls, Xiaoxi Huang, Xue Chang, Hongrui Zhang, David Pesquera, Sujit Das, Dmitri Nikonov, Ian Young, Long-Qing Chen, Lane W. Martin, Yen-Lin Huang, Jorge Íñiguez, Ramamoorthy Ramesh
Published: 2022-03-02
DOI: 10.1038/s41467-022-28622-z
Source: Full article
AbstractReducing the switching energy of ferroelectric thin films remains an important goal in the pursuit of ultralow-power ferroelectric memory and logic devices. Here, we elucidate the fundamental role of lattice dynamics in ferroelectric switching by studying both freestanding bismuth ferrite (BiFeO3) membranes and films clamped to a substrate. We observe a distinct evolution of the ferroelectric domain pattern, from striped, 71° ferroelastic domains (spacing of ~100 nm) in clamped BiFeO3films, to large (10’s of micrometers) 180° domains in freestanding films. By removing the constraints imposed by mechanical clamping from the substrate, we can realize a ~40% reduction of the switching voltage and a consequent ~60% improvement in the switching speed. Our findings highlight the importance of a dynamic clamping process occurring during switching, which impacts strain, ferroelectric, and ferrodistortive order parameters and plays a critical role in setting the energetics and dynamics of ferroelectric switching.