Thermally Activated Dynamics in 2D Colloidal Glasses and Crystals

二维胶体玻璃和晶体中的热激活动力学

• 批准号: 2203380
• 负责人: Xinsheng Ling
• 金额: $ 65.11万
• 依托单位: Brown University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-01 至 2025-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2203380&HistoricalAwards=false
• 关键词: Thermally; Activated; Dynamics; 2D; Colloidal

Non-technical abstract: In this project, the team seeks to uncover the microscopic mechanism(s) by which many materials change suddenly from a liquid to a solid without the usual crystallization process. The most familiar one is the window glass. Whether the window glass is a slowly aging liquid or a true solid is a longstanding unresolved question in science. Building on the recent research in two-dimensional (2D) colloidal glasses, the team plans to use both experiment and theory to study the origin(s) of the glass transition. The experimental and theoretical activities will benefit each other, providing motivation and testing of the hypotheses. The results of this research can benefit scientists and engineers in designing new materials. For example, understanding the mechanism(s) of how impurities or particle size variations impact the stability of the glassy material may allow scientists to artificially engineer such impurities to improve the properties of the materials, similar to introducing impurities into superconductors to make stronger magnets. The proposed research provides excellent training for two Ph.D. students, and undergraduate and master students in condensed matter physics. Training the next generation American scientists in materials science is of great importance in maintaining the US preeminence in science and technology. Technical abstract:The team plans to use video microscopy and Monte Carlo simulations to study two sets of related questions in condensed matter physics: (1) What is the microscopic mechanism in the recently discovered 2D colloidal glasses of anisotropic particles? (2) Does an array of edge dislocations formed along a low-angle grain boundary in a 2D colloidal crystal undergo a finite temperature phase transition and what happens to the phase transition when there are impurity particles in the hosting 2D crystal? The underlying fundamental question is how phases of matter and phase transitions are impacted by disorder. The first project will investigate the physical mechanism of a two-step 2D colloidal glass transition of rods. The proposed experiments will be used to distinguish various competing scenarios of the glass transition in 2D. The second project is to study a possible novel phase transition in an array of edge dislocations formed along a low-angle grain boundary in a 2D colloidal crystal and the effects of disorder on the phase transition and dynamics. The results will have a significant impact on the understanding of defects and the glassy states in condensed matter systems. The results of this research can help scientists and engineers in designing new materials for the benefit of society.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

非技术摘要：在这个项目中，该团队试图揭示许多材料在没有通常的结晶过程的情况下突然从液体变成固体的微观机制。 最熟悉的是窗户玻璃。 窗玻璃是一种缓慢老化的液体还是真正的固体，这是科学界长期悬而未决的问题。 基于最近对二维（2D）胶体玻璃的研究，该团队计划使用实验和理论来研究玻璃化转变的起源。实验和理论活动将相互受益，为假设提供动力和检验。 这项研究的结果可以使科学家和工程师在设计新材料时受益。例如，了解杂质或粒度变化如何影响玻璃质材料稳定性的机制，可以让科学家人工设计这些杂质以改善材料的性能，类似于将杂质引入超导体以制造更强的磁体。 该研究为两名博士生提供了良好的培训。学生，本科生和硕士生在凝聚态物理。 培养下一代美国材料科学家对保持美国在科学技术领域的领先地位至关重要。 技术摘要：该团队计划使用视频显微镜和蒙特卡罗模拟来研究凝聚态物理中的两组相关问题：（1）最近发现的各向异性颗粒的2D胶体玻璃中的微观机制是什么？(2)二维胶体晶体中沿小角度晶界沿着形成的刃型位错阵列是否经历有限温度相变？当晶体中存在杂质颗粒时，相变会发生什么？ 潜在的基本问题是物质的相和相变如何受到无序的影响。 第一个项目将研究棒的两步二维胶体玻璃化转变的物理机制。拟议的实验将用于区分各种竞争的情况下，在2D的玻璃化转变。第二个项目是研究二维胶体晶体中沿小角度晶界沿着形成的刃位错阵列中可能的新相变以及无序对相变和动力学的影响。这些结果对于理解凝聚态系统中的缺陷和玻璃态具有重要的意义。这项研究的结果可以帮助科学家和工程师设计新材料，造福社会。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。