Discovering minimum energy pathways via distortion symmetry groups
Discovering minimum energy pathways via distortion symmetry groups
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DOI：
10.1103/physrevb.98.085107
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发表时间：
2018-04
影响因子：
3.7
通讯作者：
Jason M. Munro;H. Akamatsu;Haricharan Padmanabhan;Vincent S Liu;Yin Shi;Long-Qing Chen;B. K. Vanleeuwen-B.-K.
中科院分区：
文献类型：
--
作者：
Jason M. Munro;H. Akamatsu;Haricharan Padmanabhan;Vincent S Liu;Yin Shi;Long-Qing Chen;B. K. Vanleeuwen-B.-K.
物理系统沿着能量势垒最小的路径从一种状态演化到另一种状态。多维搜索方法的目标是在没有对能量格局的先验知识的情况下，在动力学过程的初始状态和最终状态之间找到这样的最小能量路径。然而，在许多情况下，用户必须重复提供初始猜测路径，从而意味着最终结果的可靠性在很大程度上取决于用户。最近，作为对路径对称性的完整描述的“扭曲对称群”的概念被引入。通过这一点，实现了一种新的框架，它提供了一种强大的手段来将可能路径的无限集合分类为有限数量的对称等价子集，然后使用严格的群论方法系统地探索每个子集。这种方法，我们称之为失真对称方法，被证明是导致在适当和不适当的铁电材料中以及在多铁电体中研究体铁电开关和磁畴壁运动的先前隐藏的路径的结果。这些结果为在实验上观察到的${\mathrm{Ca}}_{3}{\mathrm{Ti}}_{2}{\mathrm{O}}_{7}$，磁区壁上开关路径的成核以及极化开关如何在不反转磁化的情况下进行提供了新的物理见解。此外，我们还演示了如何使用从高度对称的路径中的对称性破缺来探测非伊辛(Bloch和N‘eel)极化分量，这些非伊辛(Bloch和N’eel)极化分量被积分到涉及到开关的瞬态态。扭曲对称方法适用于从结构、电子和磁扭曲、扩散和相变在内的各种物理现象。
Physical systems evolve from one state to another along paths of least energy barrier. Without a priori knowledge of the energy landscape, multidimensional search methods aim to find such minimum energy pathways between the initial and final states of a kinetic process. However, in many cases, the user has to repeatedly provide initial guess paths, thus implying that the reliability of the final result is heavily user-dependent. Recently, the idea of ``distortion symmetry groups'' as a complete description of the symmetry of a path has been introduced. Through this, a new framework is enabled that provides a powerful means of classifying the infinite collection of possible pathways into a finite number of symmetry equivalent subsets, and then exploring each of these subsets systematically using rigorous group theoretical methods. The method, which we name the distortion symmetry method, is shown to lead to the discovery of previously hidden pathways for the case studies of bulk ferroelectric switching and domain wall motion in proper and improper ferroelectrics, as well as in multiferroic switching. These provide novel physical insights into the nucleation of switching pathways at experimentally observed domain walls in ${\mathrm{Ca}}_{3}{\mathrm{Ti}}_{2}{\mathrm{O}}_{7}$, as well as how polarization switching can proceed without reversing magnetization in ${\mathrm{BiFeO}}_{3}$. Furthermore, we demonstrate how symmetry-breaking from a highly symmetric pathway can be used to probe the non-Ising (Bloch and N\'eel) polarization components integral to transient states involved in switching in ${\mathrm{PbTiO}}_{3}$. The distortion symmetry method is applicable to a wide variety of physical phenomena ranging from structural, electronic and magnetic distortions, diffusion, and phase transitions in materials.