Charge-Density Waves: Novel X-ray Scattering Studies

该个人研究者奖将为一个项目提供资金，该项目将测量由外加电场驱动的电荷密度波在随机位置的杂质原子上的动态原子尺度结构。电荷密度波系统是无序状态下驱动周期系统的一个很好的例子。为了对这些系统的一些新理论进行定量测试，需要测量几个重要的量。这些包括稳态（平衡）动力学的测量和电子自由度和晶格自由度之间耦合的测量。该项目将(a)继续发展x射线光子相关光谱学（在先进光子源），用于平衡动力学的测量，并(b)评估（在CHESS）使用共振-弹性散射将电子的响应与晶格的响应分离的可行性。这些测量的潜在影响很大，因为结果直接关系到各种系统，包括：磁场驱动的磁泡晶格，维格纳晶体，电场驱动的胶体悬浮液，约瑟夫森结驱动阵列，以及衬底上晶体的生长。该项目对促进教育和人力资源开发的影响包括继续研究小组在本科、研究生和博士后阶段积极寻找、招聘和支持女性和代表性不足的少数民族的实践。x射线衍射历来是在原子长度尺度上测量物质结构的首选技术。随着时间分辨x射线技术的不断发展，在化学、物理和生物过程中，原子的位置可以在更快的时间尺度上确定。时间分辨x射线测量跨越从原子到宏观距离的长度尺度和从百万分之一到1000秒的时间尺度。这个个人研究项目将开发新的x射线技术来研究凝聚态物理中的各种问题。在研究准一维金属NbSe3中电荷密度波的过程中，将出现x射线技术的发展。已知该系统是具有大量内部自由度的物理系统的近乎理想的实现，这些自由度可以被驱动过无序，从而形成一个。使用新的改进技术是很好的。该项目将(a)继续发展x射线光子相关光谱学（在先进光子源），用于平衡动力学的测量，并(b)评估（在CHESS）使用共振-弹性散射将电子的响应与晶格的响应分离的可行性。这些测量的潜在影响是巨大的，因为结果直接关系到各种各样的其他系统，其中一些具有技术应用的潜力。该项目对促进教育和人力资源开发的影响包括继续研究小组在本科、研究生和博士后阶段积极寻找、招聘和支持女性和代表性不足的少数民族的实践。

This individual investigator award will provide funds for a project to measure the dynamic atomic-scale structure of charge-density waves driven by an applied electric field over randomly located impurity atoms. Charge density wave systems are a good example of a driven periodic system in the presence of disorder. To perform quantitative tests of some novel theories for such systems, several important quantities need to be measured. These include measurements of the steady-state (equilibrium) dynamics and measurements of the coupling between the electronic and the lattice degrees of freedom. This project will (a) continue to develop X-ray Photon Correlation Spectroscopy (at the Advanced Photon Source) for measurements of the equilibrium dynamics and will (b) assess (at CHESS) the feasibility of using resonant-elastic-scattering to separate the response of the electrons from the response of the crystal lattice. The potential impact of these measurements is large as the results relate directly to a diverse array of systems including: magnetic-bubble lattices driven by a magnetic-field, Wigner crystals, colloidal suspensions driven by an electric field, driven arrays of Josephson-junctions, and the growth of crystals on substrates. The impact of this project on advancing education and human resources development includes continuing the research group's demonstrated practice of pro-actively searching out, recruiting and supporting women and under-represented minorities at the undergraduate, graduate, and postdoctoral levels.X-ray diffraction has historically been the technique of choice for measuring the structure of matter on atomic length scales. The continuing development of time-resolved x-ray techniques allows the atomic positions to be determined on ever-faster time scales during chemical, physical, and biological processes. Time-resolved x-ray measurements span length-scales from atomic to macroscopic distances and time-scales from 1 millionth to 1000 seconds. This individual investigator project will develop new x-ray techniques for studying a variety of problems in condensed-matter physics. X-ray technique development will occur in the process of studying of charge-density waves found in the quasi one-dimensional metal NbSe3. This system is known to be a nearly ideal realization of a physical system with a large number of internal degrees of freedom that can be driven over disorder, thus it forms an. excellent one which to use new improved techniques. This project will (a) continue to develop X-ray Photon Correlation Spectroscopy (at the Advanced Photon Source) for measurements of the equilibrium dynamics and will (b) assess (at CHESS) the feasibility of using resonant-elastic-scattering to separate the response of the electrons from the response of the crystal lattice. The potential impact of these measurements is large as the results relate directly to a diverse array of other systems, some of which have the potential for technological applications.. The impact of this project on advancing education and human resources development includes continuing the research group's demonstrated practice of pro-actively searching out, recruiting and supporting women and under-represented minorities at the undergraduate, graduate, and postdoctoral levels.