Angle-Resolved Photoemission Experiments of Correlated Electronic Systems

技术：高分辨率角分辨光电子能谱(ARPES)将用于研究相关电子系统的电子结构，特别是巨磁阻氧化物。该计划过去的工作已经产生了关于CMR氧化物的最大的已发表的电子结构信息，这使得我们现在可以打开更深层次的问题，其中许多远远超出了锰氧化物的范围。此外，这项工作还与多个X射线和中子散射组、一个光学组和一个计算能带结构、关联效应和光电发射矩阵元素的理论组进行了非常重要和强大的合作。该计划将主要利用伯克利高级光源的高分辨率光电发射光束线。该活动的一个重要组成部分是对学生进行光学、固体物理和同步辐射领域的跨学科培训。此外，P.I.还领导了一项REU(本科生研究体验)计划，并将继续将本科生纳入这项研究。非技术：爱因斯坦因光电效应而获得诺贝尔奖，光电效应是指入射光子(单个光包)从固体中射出电子。这项技术已经成熟，可以说是对固体中电子的量子力学状态的最强大的探测器。我们将应用这项技术来研究一种特别有趣和潜在有用的效应，即巨磁电阻或CMR。在CMR材料中，施加磁场会引起电阻的“巨大”变化(高达11个数量级)，变化幅度可能很大。我们的目标是了解这些材料中导致其独特电磁性能的基本量子力学相互作用。该计划将主要利用伯克利高级光源的高分辨率光电发射光束线，该光源是美国卓越的同步辐射设备，生产软X射线。该活动的一个重要组成部分是对学生进行光学、固体物理和同步辐射领域的跨学科培训。此外，P.I.还领导了一项REU(本科生研究体验)计划，并将继续将本科生纳入这项研究。

Technical: High resolution angle resolved photoemission (ARPES) will be used to study the electronic structure of correlated electron systems, particularly colossal magnetoresistive (CMR) oxides. Past work from this program has produced the largest body of published electronic structure information on CMR oxides which now allows us to open the next level of even deeper questions, many of which transcend far beyond the manganites. Also setting this work apart are very important and powerful collaborations with multiple x-ray and neutron scattering groups, an optics group, and a theory group for calculation of the band structure, correlation effects, and photoemission matrix elements. The program will principally utilize high resolution photoemission beamlines at the Advanced Light Source, Berkeley. An important component of the activity is the interdisciplinary training of students in the fields of optics, solid state physics, and synchrotron radiation. In addition, the P.I. leads an REU (Research Experience for Undergraduates) program and will continue to include undergraduates in this research.Non-Technical: Einstein received his Nobel prize for the photoelectric effect, in which an incident photon (individual packet of light) ejects an electron from a solid. This technique has matured into what is arguably the most powerful probe of the quantum-mechanical state of the electrons within a solid. We will apply this technique to study a particularly interesting and potentially useful effect, colossal magnetoresistance or CMR. In CMR materials, the application of a magnetic field induces "colossal" (up to 11 orders of magnitude) changes in electrical resistance which may be many. Our goal is to understand the basic quantum mechanical interactions in these materials that is responsible for their unique electrical and magnetic properties. The program will principally utilize high resolution photoemission beamlines at the Advanced Light Source, Berkeley, which is the nation's preeminent synchrotron radiation facility producing soft X-rays. An important component of the activity is the interdisciplinary training of students in the fields of optics, solid state physics, and synchrotron radiation. In addition, the P.I. leads an REU (Research Experience for Undergraduates) program and will continue to include undergraduates in this research.