Investigation of the Electronic Structure of High Temperature Superconductors and Related Materials

高温超导体及相关材料的电子结构研究

• 批准号: 9311566
• 负责人: Zhi-Xun Shen
• 金额: $ 22万
• 依托单位: Stanford University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-02-15 至 1998-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9311566&HistoricalAwards=false
• 关键词: Investigation; Electronic; Structure; Temperature; Superconductors

9311566 Shen High energy resolution angle-resolved photoemission measurements will be carried out on high quality single crystal samples. Doping of the samples will allow to vary Tc. The photoemission studies are aimed at understanding the gap anisotropy in HTS materials where an improved energy and angular resolution will be utilized. The study of Bi2212 will be extended to YBCO, TI2212, TI2201, and NCCO. Studies of the normal state will correlate the results of photoemission measurements with transport data aimed at understanding the doping behavior of Mott insulators. High efficiency core level photoemission spectroscopy will be used to investigate changes in the local electronic structure due to the opening of the superconducting gap. The proximity effect studied near normal metal/superconductor interfaces and ferromagnetic materials will be investigated with respect to the role of oxygen in determining differences in the electronic structure of transition metals and transition metal oxides. %%% Photoemission is a powerful experimental tool in which impinging radiation leads to the ejection of electronic carriers from a solid. Measurement of the energy and angle of emission can yield important information about the electronic structure of the solid. The photoemission technique has proved to be an excellent technique to study the electronic properties of high temperature superconductors. In the present study the technique is extended to various different materials which are available as very high quality single crystal samples. A much improved spectrometer will be employed in this work. The technique will be extended to other materials, notable ferromagnetic solids. Of particular interest will be to compare transition metals such as nickel and iron with their respective oxides. ***

高能量分辨率角分辨光电发射测量将在高质量的单晶样品上进行。样品的掺杂将允许改变Tc。光发射研究的目的是了解高温超导材料的间隙各向异性，从而提高能量和角分辨率。Bi2212的研究将扩展到YBCO、TI2212、TI2201和NCCO。正常状态的研究将把光发射测量结果与旨在理解莫特绝缘体掺杂行为的输运数据联系起来。高效率的核心能级光电发射光谱将用于研究由于超导隙的打开而引起的局部电子结构的变化。在正常金属/超导体界面和铁磁材料附近研究的邻近效应将研究氧在决定过渡金属和过渡金属氧化物电子结构差异中的作用。光电发射是一种强大的实验工具，在这种实验中，撞击辐射导致电子载流子从固体中喷射出来。测量发射能量和角度可以得到关于固体电子结构的重要信息。光电发射技术已被证明是研究高温超导体电子特性的一种优良技术。在目前的研究中，该技术被扩展到各种不同的材料，这些材料可以作为非常高质量的单晶样品。在这项工作中将使用一种改进得多的光谱仪。这项技术将扩展到其他材料，特别是铁磁性固体。特别有趣的将是比较过渡金属，如镍和铁及其各自的氧化物。＊＊＊