Atomic-level theoretical and experimental study of lattice dislocations in perovskites

钙钛矿晶格位错的原子级理论与实验研究

• 批准号: 40485010
• 负责人: Dr. Matous Mrovec
• 金额: --
• 依托单位: Max-Planck-Institut für Intelligente Systeme
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2008
• 资助国家: 德国
• 起止时间: 2007-12-31 至 2012-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/40485010?language=en
• 关键词: Atomic; level; theoretical; experimental; study

The project aims to investigate the structure and energetics of dislocations in ceramic oxide materials with mixed ionic-covalent bonding by means of atomistic simulations, electronicstructure calculations, and transmission electron microscopy. We will study structural and compositional features of dislocation cores and related planar defects (stacking faults, antiphase and grain boundaries) in perovskite compounds, namely SrTiO3, BaTiO3 and PbTiO3. First-principles density functional theory will be used to calculate properties of the extended defects with high accuracy and reliability. These results will serve further to validate empirical analytic potentials for electrostatic and repulsive ion-ion interactions. With such potentials, atomistic simulations of dislocation-core models consisting of large numbers of atoms will be carried out in order to adapt and apply approaches of continuum theory and atomistic simulation developed for dislocation cores of metals to simulations of ceramic materials with prevalent ionic bonding. Special care will be given to correct handling of long-range elastic as well as electrical boundary conditions. The atomistic structure and chemical composition of dislocation cores in SrTiO3 will be studied by transmission electron microscopy. These results will serve as an important reference for the atomistic simulations. We expect that our proposed investigations will significantly improve the scientific understanding of dislocations in perovskite materials and will help to clarify the influence of dislocations on functional properties of electro-active devices.

该项目旨在通过原子模拟、电子结构计算和透射电子显微镜研究具有混合离子-共价键合的陶瓷氧化物材料中位错的结构和能量。我们将研究钙钛矿化合物中位错核心和相关平面缺陷（堆垛层错，反相和晶界）的结构和成分特征，即SrTiO 3，BaTiO 3和PbTiO 3。第一性原理密度泛函理论将被用于计算扩展缺陷的性质，具有高精度和可靠性。这些结果将进一步验证静电和排斥离子-离子相互作用的经验解析势。有了这样的潜力，原子模拟的位错核心模型组成的大量的原子将进行调整和应用的连续介质理论和原子模拟的方法开发的位错核心的金属与普遍的离子键合的陶瓷材料的模拟。将特别注意正确处理长程弹性和电边界条件。用透射电子显微镜研究了SrTiO_3中位错核的原子结构和化学组成。这些结果将作为原子模拟的重要参考。我们希望我们提出的研究将显着提高钙钛矿材料中位错的科学理解，并将有助于澄清位错对电活性器件功能特性的影响。