Karpov D, Liu Z, Rolo T Dos Santos, Harder R, Balachandran P V, Xue D, Lookman T, Fohtung E
Department of Physics, New Mexico State University, Las Cruces, NM, 88003, USA.
Department of General Physics, Physical-Technical Institute, National Research Tomsk Polytechnic University, Tomsk, 634050, Russia.
Nat Commun. 2017 Aug 17;8(1):280. doi: 10.1038/s41467-017-00318-9.
Topological defects of spontaneous polarization are extensively studied as templates for unique physical phenomena and in the design of reconfigurable electronic devices. Experimental investigations of the complex topologies of polarization have been limited to surface phenomena, which has restricted the probing of the dynamic volumetric domain morphology in operando. Here, we utilize Bragg coherent diffractive imaging of a single BaTiO nanoparticle in a composite polymer/ferroelectric capacitor to study the behavior of a three-dimensional vortex formed due to competing interactions involving ferroelectric domains. Our investigation of the structural phase transitions under the influence of an external electric field shows a mobile vortex core exhibiting a reversible hysteretic transformation path. We also study the toroidal moment of the vortex under the action of the field. Our results open avenues for the study of the structure and evolution of polar vortices and other topological structures in operando in functional materials under cross field configurations.Imaging of topological states of matter such as vortex configurations has generally been limited to 2D surface effects. Here Karpov et al. study the volumetric structure and dynamics of a vortex core mediated by electric-field induced structural phase transition in a ferroelectric BaTiO nanoparticle.
自发极化的拓扑缺陷作为独特物理现象的模板以及可重构电子器件的设计，受到了广泛研究。对极化复杂拓扑结构的实验研究一直局限于表面现象，这限制了对动态体积畴形态的原位探测。在此，我们利用复合聚合物/铁电电容器中单个钛酸钡纳米颗粒的布拉格相干衍射成像，来研究由涉及铁电畴的竞争相互作用形成的三维涡旋的行为。我们对外加电场影响下结构相变的研究表明，一个移动的涡旋核心呈现出可逆的滞后转变路径。我们还研究了电场作用下涡旋的环形矩。我们的结果为在交叉场配置下原位研究功能材料中极性涡旋和其他拓扑结构的结构与演化开辟了道路。对诸如涡旋构型等物质拓扑态的成像通常仅限于二维表面效应。在此，卡尔波夫等人研究了铁电钛酸钡纳米颗粒中由电场诱导的结构相变介导的涡旋核心的体积结构和动力学。
