Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA.
Extreme Materials Initiative, Geophysical Laboratory, Carnegie Institution for Science, Washington, DC, 20015, USA.
Nat Commun. 2019 Mar 20;10(1):1282. doi: 10.1038/s41467-019-09207-9.
Deterministic creation of multiple ferroelectric states with intermediate values of polarization remains challenging due to the inherent bi-stability of ferroelectric switching. Here we show the ability to select any desired intermediate polarization value via control of the switching pathway in (111)-oriented PbZrTiO films. Such switching phenomena are driven by kinetic control of the volume fraction of two geometrically different domain structures which are generated by two distinct switching pathways: one direct, bipolar-like switching and another multi-step switching process with the formation of a thermodynamically-stable intermediate twinning structure. Such control of switching pathways is enabled by the competition between elastic and electrostatic energies which favors different types of ferroelastic switching that can occur. Overall, our work demonstrates an alternative approach that transcends the inherent bi-stability of ferroelectrics to create non-volatile, deterministic, and repeatedly obtainable multi-state polarization without compromising other important properties, and holds promise for non-volatile multi-state functional applications.
由于铁电开关的固有双稳性，确定性地产生具有中间极化值的多个铁电状态仍然具有挑战性。在这里，我们展示了通过控制（111）取向的 PbZrTiO 薄膜中的开关路径，选择任何所需中间极化值的能力。这种开关现象是由两种不同的开关路径产生的两种几何上不同的畴结构的体积分数的动力学控制驱动的：一种是直接的双极型开关，另一种是具有热力学稳定中间孪晶结构形成的多步开关过程。这种开关路径的控制是由弹性和静电能之间的竞争实现的，这种竞争有利于可能发生的不同类型的铁弹性开关。总的来说，我们的工作展示了一种替代方法，超越了铁电体的固有双稳性，在不损害其他重要性质的情况下，创建非易失性、确定性和可重复获得的多态极化，为非易失性多态功能应用提供了前景。
