MRI: Acquisition of an Ultrahigh-Resolution Photoelectron Spectrometer for Education and Research on Complex and Low-Dimensional Materials

MRI：购买超高分辨率光电子能谱仪，用于复杂和低维材料的教育和研究

• 批准号: 0421153
• 负责人: Hanno Weitering
• 金额: --
• 依托单位: University of Tennessee Knoxville
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-08-01 至 2007-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0421153&HistoricalAwards=false
• 关键词: MRI; Acquisition; Ultrahigh; Resolution; Photoelectron

Nearly all materials properties are determined by electrons close to the Fermi level, usually within 100 meV. In order to probe the behavior of electrons in this energy range, one needs to employ spectroscopy with ultrahigh resolution. This project entails the acquisition of an ultrahigh-resolution photoemission spectrometer of the Scienta type, which offers the best resolution that is currently achievable. This instrumentation will be used to investigate the electronic states in a wide variety of advanced electronic materials, including complex transition metal oxides, thin film nanostructures, organic superconductors, and atomic-wire arrays. Coupled with other spectroscopic methods, such as inelastic neutron scattering for probing spin and lattice excitations, and optical spectroscopy and Electron Energy Loss Spectroscopy for charge dynamics, it will enable researchers to unravel the highly complex entanglement of the spin, charge, and lattice degrees of freedom in these exotic materials. The new instrumentation will be based on campus, not at the synchrotron, so that students and faculty can have easy access and copious amounts of high quality photoemission time. The proposed science and new infrastructure will provide an excellent setting for the education and training of internationally competitive students and postdocs.Nearly all materials properties are determined by electrons close to the Fermi level, which represents the highest occupied energy level. Examples include electrical conductivity, magneto-resistance, superconductivity, and magnetism. In order to understand these important materials properties, one should probe the electrons near the Fermi level with ultrahigh resolution spectroscopy. From the late 1980s, Angular Resolved Photo-Emission Spectroscopy has been intensively applied to unravel the origins of superconductivity in high-temperature superconductors. In recent years the resolution of photoemission experiments has improved so much that electrons within a fraction of a milli-electronvolt around Fermi level can now be distinguished. Many of these potentially prize-winning studies have been published in highly prestigious journals because the ever increasing resolution unraveled novel properties that challenged the community and triggered new discovery. This project entails the acquisition of the world's best ultrahigh-resolution photoemission apparatus for the University of Tennessee. It will be used to study a wide variety of advanced electronic materials, including complex transition-metal oxides, thin film nanostructures, organic superconductors, and atom-wire arrays. A key aspect of the proposed research activities is that the powerful capabilities of this instrument will be combined with the local, complementary expertise and capabilities in neutron scattering and materials synthesis, thus providing researchers in East Tennessee with a competitive edge. The new instrumentation will be based on the Knoxville campus, not at a national synchrotron facility, so that students and faculty can have easy access and copious amounts of high quality photoemission time. The proposed science and infrastructure will also be accessible to the African American and Hispanic minority-student population at Florida International University and provide an excellent setting for the education and training of internationally competitive students and postdocs from diverse backgrounds.

几乎所有材料的性质都是由接近费米能级的电子决定的，通常在100 meV以内。为了探测电子在这一能量范围内的行为，需要使用分辨率为1000的光谱学。该项目需要购买Scienta型超高分辨率光电发射光谱仪，该光谱仪提供目前可实现的最佳分辨率。该仪器将用于研究各种先进电子材料中的电子状态，包括复杂的过渡金属氧化物，薄膜纳米结构，有机超导体和原子线阵列。再加上其他光谱方法，如探测自旋和晶格激发的非弹性中子散射，以及用于电荷动力学的光学光谱和电子能量损失光谱，它将使研究人员能够解开这些奇异材料中自旋，电荷和晶格自由度的高度复杂纠缠。新的仪器将基于校园，而不是在同步加速器，使学生和教师可以很容易地访问和大量的高质量的光电发射时间。拟议中的科学和新的基础设施将为具有国际竞争力的学生和博士后的教育和培训提供一个良好的环境。几乎所有的材料特性都是由接近费米能级的电子决定的，费米能级代表了最高的占据能级。例子包括导电性、磁阻、超导性和磁性。为了了解这些重要的材料特性，人们应该用高分辨光谱探测费米能级附近的电子。从20世纪80年代后期开始，角分辨光电子能谱（Angular Resolved Photo-Emission Spectroscopy）被广泛应用于揭示高温超导体中超导性的起源。近年来，光电发射实验的分辨率有了很大的提高，现在可以分辨出费米能级附近几分之一毫伏电子伏的电子。这些可能获奖的研究中有许多已经在极负盛名的期刊上发表，因为不断提高的分辨率揭示了挑战社区并引发新发现的新特性。该项目需要为田纳西大学购买世界上最好的超高分辨率光电发射设备。它将用于研究各种先进的电子材料，包括复杂的过渡金属氧化物，薄膜纳米结构，有机超导体和原子线阵列。 拟议研究活动的一个关键方面是，该仪器的强大功能将与当地的互补专业知识和中子散射和材料合成能力相结合，从而为东田纳西州的研究人员提供竞争优势。新的仪器将基于诺克斯维尔校园，而不是在国家同步加速器设施，使学生和教师可以很容易地访问和大量的高质量的光电发射时间。拟议的科学和基础设施也将提供给非裔美国人和西班牙裔少数民族学生人口在佛罗里达国际大学，并提供了一个良好的环境，为教育和培训具有国际竞争力的学生和博士后来自不同的背景。