![]() In the case of proper ferroelectrics 3, 4, 5, 6, where the spontaneous polarization arises from the freezing of a soft-phonon mode at the Curie temperature, the coupling between the dipolar order and the lattice is much stronger than, for example, the coupling of spins to the lattice in ferromagnets 7, 8, 9. The last three decades have witnessed a significant interest in the science and technology of ferroelectric thin films, driven by the fascinating fundamental physics of the polar state in reduced dimensions as well as the technological applications, for example, in nonvolatile memories 1, 2, which utilize the switchable nature of the ferroelectric polarization to store information. 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. 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. We observe a distinct evolution of the ferroelectric domain pattern, from striped, 71° ferroelastic domains (spacing of ~100 nm) in clamped BiFeO 3 films, to large (10’s of micrometers) 180° domains in freestanding films. Here, we elucidate the fundamental role of lattice dynamics in ferroelectric switching by studying both freestanding bismuth ferrite (BiFeO 3) membranes and films clamped to a substrate. Reducing the switching energy of ferroelectric thin films remains an important goal in the pursuit of ultralow-power ferroelectric memory and logic devices. Nature Communications volume 13, Article number: 1110 ( 2022) The role of lattice dynamics in ferroelectric switching ![]()
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