Wei Xian-Kui, Prokhorenko Sergei, Wang Bi-Xia, Liu Zenghui, Xie Yu-Juan, Nahas Yousra, Jia Chun-Lin, Dunin-Borkowski Rafal E, Mayer Joachim, Bellaiche Laurent, Ye Zuo-Guang
Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich GmbH, Jülich, Germany.
Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, NC, USA.
Nat Commun. 2021 Sep 7;12(1):5322. doi: 10.1038/s41467-021-25543-1.
Phase transition describes a mutational behavior of matter states at a critical transition temperature or external field. Despite the phase-transition orders are well sorted by classic thermodynamic theory, ambiguous situations interposed between the first- and second-order transitions were exposed one after another. Here, we report discovery of phase-transition frustration near a tricritical composition point in ferroelectric Pb(ZrTi)O. Our multi-scale transmission electron microscopy characterization reveals a number of geometrically frustrated microstructure features such as self-assembled hierarchical domain structure, degeneracy of mesoscale domain tetragonality and decoupled polarization-strain relationship. Associated with deviation from the classic mean-field theory, dielectric critical exponent anomalies and temperature dependent birefringence data unveil that the frustrated transition order stems from intricate competition of short-range polar orders and their decoupling to long-range lattice deformation. With supports from effective Hamiltonian Monte Carlo simulations, our findings point out a potentially universal mechanism to comprehend the abnormal critical phenomena occurring in phase-transition materials.
相变描述了物质状态在临界转变温度或外部场作用下的突变行为。尽管经典热力学理论已将相变顺序很好地进行了分类，但在一阶和二阶转变之间出现的模糊情况却相继被揭示出来。在此，我们报告了在铁电体Pb(ZrTi)O的三临界点附近发现的相变受挫现象。我们的多尺度透射电子显微镜表征揭示了许多几何受挫的微观结构特征，如自组装的分层畴结构、中尺度畴四方性的简并以及解耦的极化 - 应变关系。与偏离经典平均场理论相关联，介电临界指数异常和温度相关的双折射数据表明，受挫的转变顺序源于短程极性有序的复杂竞争及其与长程晶格变形的解耦。在有效的哈密顿蒙特卡罗模拟的支持下，我们的发现指出了一种潜在的通用机制，以理解相变材料中出现的异常临界现象。
