Han Bo, Zhu Ruixue, Li Xiaomei, Wu Mei, Ishikawa Ryo, Feng Bin, Bai Xuedong, Ikuhara Yuichi, Gao Peng
Electron Microscopy Laboratory and International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China.
Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
Phys Rev Lett. 2021 Jun 4;126(22):225702. doi: 10.1103/PhysRevLett.126.225702.
The broken symmetry at structural defects such as grain boundaries (GBs) discontinues chemical bonds, leading to the emergence of new properties that are absent in the bulk owing to the couplings between the lattice and other parameters. Here, we create a two-dimensional antiferrodistortive (AFD) strontium titanate (SrTiO_{3}) phase at a Σ13(510)/[001] SrTiO_{3} tilt GB at room temperature. We find that such an anomalous room-temperature AFD phase with the thickness of approximate six unit cells is stabilized by the charge doping from oxygen vacancies. The localized AFD originated from the strong lattice-charge couplings at a SrTiO_{3} GB is expected to play important roles in the electrical and optical activity of GBs and can explain past experiments such as the transport properties of electroceramic SrTiO_{3}. Our study also provides new strategies to create low-dimensional anomalous elements for future nanoelectronics via grain boundary engineering.
诸如晶界（GBs）等结构缺陷处的对称性破缺会使化学键中断，由于晶格与其他参数之间的耦合，从而导致出现大块材料中不存在的新特性。在此，我们在室温下于Σ13(510)/[001] SrTiO₃倾斜晶界处创建了二维反铁畸变（AFD）钛酸锶（SrTiO₃）相。我们发现，这种厚度约为六个晶胞的异常室温AFD相通过氧空位的电荷掺杂得以稳定。源自SrTiO₃晶界处强晶格 - 电荷耦合的局域化AFD有望在晶界的电学和光学活性中发挥重要作用，并能解释过去的实验，如电陶瓷SrTiO₃的输运性质。我们的研究还提供了新策略，可通过晶界工程为未来的纳米电子学创建低维异常元素。
