Cheng Shaobo, Li Jun, Han Myung-Geun, Deng Shiqing, Tan Guotai, Zhang Xixiang, Zhu Jing, Zhu Yimei
School of Materials Science and Engineering, Tsinghua University, Beijing 100084, People's Republic of China.
Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, New York 11973, USA.
Phys Rev Lett. 2017 Apr 7;118(14):145501. doi: 10.1103/PhysRevLett.118.145501. Epub 2017 Apr 5.
We report structural transformation of sixfold vortex domains into two-, four-, and eightfold vortices via a different type of topological defect in hexagonal manganites. Combining high-resolution electron microscopy and Landau-theory-based numerical simulations, we investigate the remarkable atomic arrangement and the intertwined relationship between the vortex structures and the topological defects. The roles of their displacement field, formation temperature, and nucleation sites are revealed. All conceivable vortices in the system are topologically classified using homotopy group theory, and their origins are identified.
我们报道了通过六方锰氧化物中一种不同类型的拓扑缺陷,六重涡旋畴向二重、四重和八重涡旋的结构转变。结合高分辨率电子显微镜和基于朗道理论的数值模拟,我们研究了显著的原子排列以及涡旋结构与拓扑缺陷之间的相互关系。揭示了它们的位移场、形成温度和成核位点的作用。利用同伦群理论对系统中所有可能的涡旋进行拓扑分类,并确定了它们的起源。