CAREER: Non-equilibrium Dynamics in Cuprate Superconductors Studied by Coherent Ultrafast Spectroscopy and Ultrafast Electron Diffraction

非技术摘要：该奖项根据2009年美国复苏和再投资法案（公法111-5）资助。这个职业奖资助一个项目，通过研究在原子尺度上发生的超快事件的动力学来了解铜酸盐的超导机制。超导性是在临界温度以下电阻的全部损失。目前，基于铜氧的铜酸盐超导体具有最高的已知转变温度。即使在这些材料中，转变温度也远低于室温，这阻碍了潜在的应用，并且超导性的机制仍然未知。这个项目将使用超短激光脉冲，使原子尺度？电影？电子动力学和晶格结构的空间和时间分辨率。从这些测量中获得的信息将有助于理解导致铜酸盐高温超导性的复杂相互作用，这反过来又可以预测具有更高转变温度的超导体。一个强有力的重点将放在发展教育和推广计划整合到这个项目的研究组成部分。该项目的教育部分将培训能够将这些技术应用于不同领域的研究生和本科生。将开发一门研究生课程，专门介绍超快技术在凝聚态物理学中的应用，其材料将通过互联网免费提供。该计划的推广部分将有助于提高K-12数学和科学教育的质量，特别是在社会经济影响地区。这将通过与以数学和科学为导向的特许学校和教育研究机构密切合作来实现。 该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。这个早期教师职业项目的目标是通过研究其低能量激发和相变的动力学来了解铜酸盐中超导性的机制。在超短光脉冲光激发后，将使用光或电子脉冲在空间和时间上探测所产生的非平衡态的恢复，提供关于电子和结构自由度的演化的信息。在高激发密度极限下，非平衡相变将被诱导到可以是热可达的或完全新颖的状态。研究这些相变的动力学将提供有关这些材料竞争状态的关键信息，并提供有关其复杂相图的线索。通过研究弱激励极限，将获得重要的见解不同的内部自由度之间的耦合的性质。一个强有力的重点将放在发展教育和推广计划整合到这个项目的研究组成部分。该项目的教育部分将培训能够将这些技术应用于不同领域的研究生和本科生。将开发一门研究生课程，专门介绍超快技术在凝聚态物理学中的应用，其材料将通过互联网免费提供。该计划的推广部分将有助于提高K-12数学和科学教育的质量，特别是在社会经济影响地区。这将通过与以数学和科学为导向的特许学校和教育研究机构密切合作来实现。

Non-Technical abstract:This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). This CAREER award funds a project to understand the mechanism of superconductivity in cuprates by studying dynamics of ultrafast events taking place at the atomic scale. Superconductivity is the total loss of electrical resistance below a critical temperature. Currently, copper oxygen based cuprate superconductors have the highest known transition temperatures. Even in these materials, the transition temperatures are far below the room temperature which hinders potential applications and the mechanism of superconductivity is still not known. This project will use ultrashort laser pulses to make atomic scale ?movies? of dynamics of electrons and the lattice structure with both spatial and temporal resolutions. Information obtained from these measurements will help to understand the complex interactions leading to high temperature superconductivity in cuprates which may in turn enable predicting superconductors with higher transition temperatures. A strong emphasis will be placed on developing education and outreach programs integrated to the research component of this project. The education component of this project will enable training of graduate and undergraduate students capable of applying these techniques to different fields. A graduate level course dedicated to the application of ultrafast techniques to condensed matter physics will be developed and its material will be made freely available through the internet. The outreach part of this program will contribute improving the quality of K-12 math and science education especially in socio-economically impacted regions. This will be achieved by working closely with math and science oriented charter schools and education research institutions. Technical abstract:This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). The goal of this Early Faculty CAREER project is to understand the mechanism of superconductivity in cuprates by studying the dynamics of their low energy excitations and phase transitions. After photoexcitation by ultrashort light pulses, the recovery of the resulting non-equilibrium state will be probed in both space and time using either light or electron pulses providing information about evolution of electronic and structural degrees of freedoms. In the high excitation density limit, non-equilibrium phase transitions will be induced into states that can be either thermally accessible or completely novel. Studying the dynamics of these phase changes will provide crucial information about the competing states of these materials and yield clues about their complex phase diagram. By studying the weak excitation limit, important insights will be obtained into the nature of couplings between different internal degrees of freedoms. A strong emphasis will be placed on developing education and outreach programs integrated to the research component of this project. The education component of this project will enable training of graduate and undergraduate students capable of applying these techniques to different fields. A graduate level course dedicated to the application of ultrafast techniques to condensed matter physics will be developed and its material will be made freely available through the internet. The outreach part of this program will contribute improving the quality of K-12 math and science education especially in socio-economically impacted regions. This will be achieved by working closely with math and science oriented charter schools and education research institutions.