Gao Peng, Liu Heng-Jui, Huang Yen-Lin, Chu Ying-Hao, Ishikawa Ryo, Feng Bin, Jiang Ying, Shibata Naoya, Wang En-Ge, Ikuhara Yuichi
Electron Microscopy Laboratory, School of Physics, Center for Nanochemistry, Peking University, Beijing 100871, China.
Collaborative Innovation Center of Quantum Matter, Beijing 100871, China.
Nat Commun. 2016 Apr 19;7:11318. doi: 10.1038/ncomms11318.
At the ferroelectric surface, the broken translational symmetry induced bound charge should significantly alter the local atomic configurations. Experimentally revealing the atomic structure of ferroelectric surface, however, is very challenging due to the strong spatial variety between nano-sized domains, and strong interactions between the polarization and other structural parameters. Here, we study surface structures of Pb(Zr0.2Ti0.8)O3 thin film by using the annular bright-field imaging. We find that six atomic layers with suppressed polarization and a charged 180° domain wall are at negatively poled surfaces, no reconstruction exists at positively poled surfaces, and seven atomic layers with suppressed polarization and a charged 90° domain wall exist at nominally neutral surfaces in ferroelastic domains. Our results provide critical insights into engineering ferroelectric thin films, fine grain ceramics and surface chemistry devices. The state-of-the-art methodology demonstrated here can greatly advance our understanding of surface science for oxides.
在铁电体表面，由平移对称性破缺引起的束缚电荷会显著改变局部原子构型。然而，由于纳米尺寸畴之间强烈的空间变化以及极化与其他结构参数之间的强相互作用，通过实验揭示铁电体表面的原子结构极具挑战性。在此，我们利用环形明场成像研究了Pb(Zr0.2Ti0.8)O3薄膜的表面结构。我们发现，在负极化表面存在六个极化受到抑制的原子层以及一个带电的180°畴壁，正极化表面不存在重构，而在铁弹性畴中名义上中性的表面存在七个极化受到抑制的原子层以及一个带电的90°畴壁。我们的结果为铁电薄膜、细晶粒陶瓷和表面化学器件的工程设计提供了关键见解。此处展示的先进方法能够极大地推动我们对氧化物表面科学的理解。
