Multiscale studies of defects in solids

我的长期目标是开发一个基于固体结构无序的材料物理框架，用于回答科学、技术和文化问题。自人类存在以来，我们就以创造性的方式利用周围的固体来改善我们的生活。固体材料的形成和使用过程中引入的缺陷可能对其物理性质产生巨大影响。通过富有成效的合作，我发现考古学中无处不在的材料是研究无序固体物理学中有趣问题的理想原型。 在接下来的五年中，我将利用物理学和考古学的融合来研究结构缺陷如何影响固体的振动特性，重点关注两个问题：（1）当固体的环境因热、压力或暴露于流体而发生变化时，固体内部的结构变化发生的速度有多快？同位素是通过振动光谱跟踪固体结构特性的理想示踪剂，因为同位素在化学上相同（电子数量相同），但质量略有不同（中子数量不同）。 最新颖的方面将是使用寿命极短的放射性同位素（寿命仅为数十分钟），以跟踪富碳固体中基于气体和基于水的结构变化的早期阶段。 最终目标是利用这些新知识来设计不易造成环境退化的材料。 (2) 不同类型的缺陷如何影响振动在固体中传播的方式？ 固体中的缺陷可以有多种形式，从原子排列的埃级差异，到固体周期性的纳米级变化，再到微观孔隙和裂缝。该项目的一个创新方面是我们在同一材料上使用不同的材料表征技术来在不同的长度尺度上研究它，因为很少看到结构缺陷的多长度尺度研究。这些结果将帮助我们识别材料中的特定无序特征，从而告诉我们它是如何随着时间的推移形成或演化的。我将获得的见解可以应用于考古学、地球化学和技术领域的研究问题。 这是因为评估固体材料的无序性可以帮助我们了解材料如何随着时间的推移而形成或演化，并且可以帮助我们识别和设计不易遭受环境退化的材料。例如，层状碳酸钙材料中的微米和纳米级结构缺陷对于资源开采很重要，因为它们影响钻井策略以及水、石油和天然气在层内和层间流动的容易程度。此外，了解氧化石墨的形成和结构稳定性将有助于开发氧化木炭的新放射性碳测年策略。

My long-term goal is to develop a materials physics framework, based on structural disorder in solids, for answering scientific, technological, and cultural questions. As long as humans have existed, we have used solids around us in creative ways to enhance our lives. Imperfections that are introduced during the formation and use of a solid material can have a dramatic influence on its physical properties. Through fruitful collaborations, I have found that ubiquitous materials in archaeology are ideal prototypes to investigate interesting problems in the physics of disordered solids. In the next 5 years, I will use this convergence of physics and archaeology to study how structural imperfections affect vibrational properties in solids by focusing on two questions:(1) How rapidly do structural changes occur within a solid when its environment changes due to heat, pressure, or exposure to fluids? Isotopes are ideal tracers for tracking structural properties of solids through vibrational spectroscopy because isotopes are chemically identical (the same number of electrons), but have a slightly different mass (a different number of neutrons). The most novel aspect will be working with extremely short-lived radioactive isotopes -- with lifetimes of tens of minutes -- in order to track the early stages of gas-based and water-based structural changes in carbon-rich solids. The final goal is to use this new knowledge to design materials that are less prone to environmental degradation. (2) How do different kinds of imperfections affect the way that vibrations propagate in a solid? Imperfections in solids can take many forms, ranging from Angstrom-scale differences in atomic arrangements, to nm-scale variations in a solid's periodicity, to microscopic pores and cracks. An innovative aspect of this project will be our use of different material characterization techniques on the same material to study it at different length scales, since it is rare to see multi-length-scale studies of structural imperfections. These results will help us to identify specific disorder signatures in a material that can tell us how it formed or evolved over time.The insights I will gain can be applied to research problems in archaeology, geochemistry, and technology sectors. This is because assessing disorder in solid materials can help us understand how a material formed or evolved over time, and can help us identify and design materials that are less prone to environmental degradation. For example, micro- and nano-scale structural defects in layered calcium carbonate materials are important for resource extraction because they affect drilling strategies, and how easily water, oil, and gas can flow within and between layers. Furthermore, understanding the formation and structural stability of graphite oxide will help develop new radiocarbon dating strategies for oxidized wood-based charcoal.