Electrodynamics of Fe-based High-Tc Superconductors

* 非技术摘要 * 超导体是一种无电阻导电的材料，这意味着当电流流过材料时没有能量损失。 如果一种材料成为超导体的温度（它的Tc）更接近室温，那么在其他应用中，使用超导输电线来传输电力将是可行的。 在当代物理学中，高Tc超导的问题几乎没有其他未解决的问题-考虑到它的丰富性，复杂性，对其他领域的影响和潜在的技术重要性。 这个个人研究者奖支持一个旨在在这个具有挑战性的问题上取得重大进展的项目。 将对最近发现的一种高Tc超导体“磷族元素化物超导体”进行一系列全面的红外研究。 该项目是由几个因素的汇合，包括最近的进展，在仪器的红外光学和新出现的可用性以及表征单晶的pnictide高Tc材料，非常适合于解决一些特定的长期存在的问题。 对于该项目的成功同样重要的是，将致力于招募有才华的研究生进入研究小组，包括属于目前在科学领域代表性不足的群体的学生。 后一项任务将通过让来自大部分学生属于代表性不足群体的机构的研究型本科生参与来完成。 此外，PI将继续为UCSD的高年级本科生和研究生提供“物理学伦理”课程。 本课程的目的是从一开始就激发科学工作的道德愿景，从而提高学生对他们的工作在社会中可能产生的巨大影响的认识。技术摘要 * 这项个人研究奖将支持对最近发现的磷属元素化物高Tc超导体进行红外研究的新努力。 拟议的实验：1）将提供至关重要的洞察到正常状态的pnictides的基本特征，包括接近磁有序状态和移动的电荷的晶格和磁激发的强耦合的作用; 2）将产生一个详细的实验图像的超导冷凝物的形成，包括在这些各向异性系统的能隙和超流密度的演变;和3）将提供所需的信息，以批判性地评估电子关联在奇异正常态性质和超导性中的作用。 该项目期望从铁基高温超导体的整个类别的固有特性中解开特定磷属元素化物家族的材料特定特性。 这项工作将促进研究生的培训，并为本科生从事科学研究提供机会。

****NON-TECHNICAL ABSTRACT****Superconductors are materials that conduct electricity without any resistance, which means there is no loss of energy when a current flows through the material. If the temperature at which a material becomes a superconductor (its Tc) were closer to room temperature, it would be practical to use superconducting transmission lines to transfer electrical power, among other applications. The problem of high-Tc superconductivity is surpassed by few, if any, other unresolved problems in contemporary physics - in view of its richness, complexity, impact on other fields and potential technological importance. This individual investigator award supports a project aimed at making significant advances in this challenging problem. A comprehensive set of infrared (IR) studies of a recently discovered family of high-Tc superconductors, the "pnictide superconductors," will be undertaken. The project is enabled by a confluence of several factors including recent progress in the development of instrumentation for IR optics and a newly emerging availability of well characterized single crystals of pnictide high-Tc materials which are ideally suited to address a number of specific long standing issues. Equally important for the success of the project will be a dedicated effort to recruit talented graduate students into the research group, including students belonging to groups currently underrepresented in science. The latter task will be accomplished by engaging in research undergraduates from institutions with a large fraction of students belonging to underrepresented groups. Furthermore, the PI will continue offering a course on "Ethics in Physics" tailored for upper division undergraduate and graduate students at UCSD. The purpose of this course is to inspire, from the very beginning, an ethical vision of scientific work thus raising students' awareness of the tremendous impact their work can have in society.****TECHNICAL ABSTRACT****This individual investigator award will support a new effort on infrared studies of recently discovered pnictide high-Tc superconductors. The proposed experiments: 1) will deliver critically important insights into the essential characteristics of the normal state of pnictides including the role of proximity to a magnetically ordered state and strong coupling of mobile charges to both lattice and magnetic excitations; 2) will produce a detailed experimental picture of the formation of the superconducting condensate including the evolution of both the energy gap and superfluid density in these anisotropic systems; and 3) will provide information needed to critically assess the role of electronic correlations in both exotic normal state properties and superconductivity. This project expects to disentangle material-specific properties of particular families of pnictides from the intrinsic characteristics generic to the entire class of iron-based high-Tc superconductors. The work will facilitate training of graduate students and provide opportunities to engage undergraduates in scientific research.