RUI: Fluctuations and Phase Transitions in Iron Pnictide Superconductors

* 技术摘要 * 该奖项支持本科院校的实验低温物理研究。电压-电流曲线的标度分析是研究正常-超导相变的重要工具。然而，最近的工作表明，这种工具的传统应用是太灵活，唯一确定的关键参数，和外在的影响，可以掩盖或破坏的相变。有了这些已知的警告，我们已经成功地应用这种技术来研究空穴掺杂的铜酸盐YBa 2Cu 3 O 7和电子掺杂的铜酸盐Pr 2-xCexCuO 4。本计画将使用相同的技术来研究新的铁磷属元素化物-122超导体（SrFe 2As 2和BaFe 2As 2）在磁场和零磁场中的相变。这项工作将导致在这种材料中的相变和铁磷属元素化物超导体和其他超导体之间的相变的差异和相似性的模型的理解。该项目还将培训实验和低温物理学的本科生，为研究生工作或工业生涯做准备。此外，为了鼓励更广泛的科学教育，该项目将促进与当地公立学校的现有外展计划，并将视频演示提交到YouTube。非技术摘要 * 该奖项支持本科院校的实验低温物理研究。“高温”超导体是在四分之一个多世纪前发现的，它仍然有着巨大的希望和巨大的挑战。前景在于希望最终制造出具有更高转变温度的超导体，挑战在于即使在25年后，我们也没有完全理解这些材料如何或为什么超导。2008年发现的由铁和砷制成的超导体是一系列显示超导性的不寻常材料中的最新材料。这个个人研究者奖支持一个项目，该项目将研究铁和砷基材料如何成为超导体，将它们与铜氧基超导体和传统的单元素超导体进行比较，所有这些都是为了了解在这些材料中产生超导性的潜在机制。拟议的研究将增加对高温超导体的了解，并有助于实现获得更高转变温度的承诺。该项目还将培训本科生最先进的样品生长，表征和测量技术。该项目还将通过促进当地学校的科学推广和通过在线视频演示促进研究，为更广泛的教育目标做出贡献。

****Technical Abstract****This award supports experimental low-temperature physics research at an undergraduate institution. The scaling analysis of voltage vs. current curves has been an invaluable tool in the study of the normal-superconducting phase transition. However, recent work has shown that the conventional application of this tool is too flexible to uniquely determine the critical parameters, and that extrinsic effects can obscure or destroy the phase transition. With these caveats known, we have successfully applied this technique to study the hole-doped cuprate YBa2Cu3O7 and the electron-doped cuprate Pr2-xCexCuO4. This project will use the same technique to examine the phase transition in the new iron pnictide-122 superconductors (SrFe2As2 and BaFe2As2) both in a magnetic field and in zero magnetic field. This work will lead to an understanding of the model that governs the phase transition in this material and the differences and similarities of the phase transition between iron pnictide superconductors and other superconductors. This project will also train undergraduate students in experimental and low-temperature physics in preparation for graduate work or industry careers. In addition, to encourage broader education in science, this project will contribute to an existing outreach program with local public schools and submit video demonstrations to YouTube.****Non-Technical Abstract****This award supports experimental low-temperature physics research at an undergraduate institution. "High-Temperature" superconductors, discovered more than a quarter of a century ago, still hold great promise and great challenges. The promise lies in the hope of eventually making superconductors with much higher transition temperatures, and the challenges lie in the fact that we do not, even 25 years later, fully understand how or why these materials superconduct. Superconductors made from iron and arsenic, discovered in 2008, are the latest in an array of unusual materials to display superconductivity. This individual investigator award supports a project that will study how iron- and arsenic-based materials become superconducting, comparing them to copper-oxygen based superconductors and conventional, single element superconductors, all in the hopes of understanding the underlying mechanism that creates superconductivity in these materials. The proposed studies will add to the knowledge of high-temperature superconductors and help fulfill the promise of attaining higher transition temperatures. This project will also train undergraduate students in state-of-the-art sample growth, characterization, and measurement techniques. This project will also contribute to broader educational goals by fostering science outreach to local schools and promoting the research via online video demonstrations.