Ultrafast Structural Dynamics in Materials at Atomic to Microscale Resolution

原子级至微米级分辨率的材料超快结构动力学

• 批准号: RGPIN-2014-04013
• 负责人: Siwick, Bradley
• 金额: $ 3.06万
• 依托单位: McGill University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=633536
• 关键词: Ultrafast; Structural; Dynamics; Materials; Atomic

In the coming years, innovation in materials physics will reside in our ability to understand and control the intimate relationships between the structure of materials and their properties, both at and far from equilibrium. This goal has been recognized as a Grand Challenge for the fundamental sciences in a recent US Department of Energy (DOE) report. This requires new tools, and the PIs research program is focused on the pioneering development of instruments and methods that can provide essential missing information on complex materials, and the structure and properties of systems far from equilibrium. This research program is expected to have a broad impact across all traditional scientific disciplines (Physics, Chemistry, Biology). In particular, the proposed studies are enabled by the very recent development of RF compressed ultrafast electron diffraction in the Siwick group at McGill. The orders of magnitude enhancement in instrumentation performance that RF compression provides has defined a new state-of-the-art for UED studies, a technique that has recently provided unprecedented views of atomic-level structural dynamics for several materials and demonstrated the ability to separate dynamical contributions that come from the reorganization of lattice structure from that which comes from changes in orbital occupancy (or charge density) through an ultrafast optically induced phase transition. Combined with the state-of-the-art ultrafast broadband reflectivity also available in the Siwick lab and the new Infrastructure for Advanced Imaging in the Montreal area (based on two one-of-a-kind dynamic and ultrafast transmission electron microscopes) the PI has at his disposal a suite of advanced characterization methods is capable of interrogating time-evolving processes in materials near the level of detail that is available from the tools we use to study the equilibrium structure/properties of materials. Through this proposal the PI will apply these breakthrough tools and world world-class capabilities to measure material structures and properties during transformations to study the effects of structural changes on material functionalities and the dynamics of optical excitation in materials on their nature scales of length (nm), time (fs–ps) and energy (meV) simultaneously. These tools will be employed to address a number of target problems of high impact, including (but not limited to): 1. The respective role of electron-electron correlations, orbital selection and lattice distortions in the metal-insulator transitions of a broad class of strongly correlated oxides. 2. Optically induced structural dynamics in a range of 'light active' organic crystals from azobenzenes and charge transfer salts to protien crystals.

在接下来的几年中，材料物理学的创新将居住在我们理解和控制材料结构及其性质之间的亲密关系的能力，无论是平衡的还是远离平衡的。在最近的美国能源部（DOE）报告中，这一目标被认为是基础科学的巨大挑战。这需要新的工具，PIS研究计划的重点是启动工具和方法的开发，这些工具和方法可以提供有关复杂材料的必不可少的信息，以及系统的结构和属性，远非均衡。预计该研究计划将在所有传统的科学学科（物理，化学，生物学）中产生广泛的影响。特别是，通过McGill的Siwick组的RF压缩超快电子衍射的最新发展实现了拟议的研究。 RF压缩提供的仪器性能的幅度提高了，定义了UED研究的新最新技术，该技术最近为多种材料提供了原子级结构动力学的前所未有的观点，并证明了分离动态贡献的能力，这些动态贡献来自于从某种程度上转移（或者是均值）（或者是均值）（或者是均值）（或者是均值）（或者是均值）。结合最先进的超快宽带反射率，在Siwick实验室以及蒙特利尔地区先进成像的新基础架构（基于两个独一无二的动态和超级传输电子显微镜）中，PI具有高级特征的套件，可以使IS的使用套件构成材料，从而估计了材料的材料，该材料是在材料中造成的。材料的等效结构/特性。通过该提案，PI将应用这些突破性工具和世界一流的能力来测量转换过程中的材料结构和特性，以研究结构变化对材料功能的影响以及材料中光兴奋的动态对其长度（NM），时间（FS – PS）和能量（MEV）的自然尺度（NM）和（MEV）的影响。这些工具将被用来解决许多高影响的目标问题，包括（但不限于）：1。电子电子相关性，轨道选择和晶格扭曲的相对作用在广泛的强相关氧化物的金属绝缘体过渡中。 2。在从偶氮苯和电荷转移到蛋白质晶体的一系列“光活性”有机晶体中的光学诱导的结构动力学。