CAREER: Spin-Resolved Imaging of Correlated Electron Systems Including Cuprates and Pnictides

这个职业奖项资助了一个研究复杂材料中电子自旋的项目。尽管金属中的电子只关心自己的事情，彼此之间几乎没有相互作用，但在所谓的“强相关电子”材料中，电子的相互作用驱动着独特的性质，这些性质令人着迷，而且往往有用。例如，所谓的高T_c超导体在经济上可行的温度下无损耗地携带电力；多铁材料允许使用磁场存储电子数据，使用电场存储磁性数据；重费米子材料拥有行为是其实际质量数千倍的电子；被称为石墨烯的简单碳片允许电子像没有质量一样快速前进。这些材料的共同点是它们的电子相互作用很强，而且人们对这些相互作用知之甚少。该项目将使用自旋极化扫描隧道显微镜，以原子分辨率测量电子自旋的能量和位置，从超导体开始。该项目还将利用这项技术来教育三个有价值的群体：哈佛大学的学生将从一门新的扫描隧道显微镜本科课程中受益；当地的小学生将被邀请参观一个工作中的科学实验室，观看真实的电子；感兴趣的公民将能够浏览一个五颜六色的网站，解释正在研究的各种迷人的材料。该技术奖为一个项目提供资金，该项目旨在为高T超导体中的电子自旋成像，包括铜酸盐和超导。这些奇异材料的共同特征是它们的电子相互作用很强，而且没有广泛成功的理论语言来描述这些所谓的“相关电子材料”。通过各种成像电子电荷相互作用的方法已经取得了长足的进步，但由于缺乏有效的工具来成像电子自旋的相互作用，人们的理解一直受到限制。该项目将使用低温自旋极化扫描隧道显微镜来测量具有原子分辨率的电子态的自旋分辨密度。特别是，将对1986年和2008年发现的仅有的两类高T_c超导体的自旋相互作用进行比较。该项目还将利用这种自旋成像技术来教育三个有价值的群体：哈佛大学的学生将受益于一门新的扫描隧道显微镜本科课程；当地的小学生将被邀请参观为真实电子成像的工作科学实验室；感兴趣的公民将能够浏览一个五颜六色的网站，解释正在研究的各种吸引人的强关联材料。

NON-TECHNICAL ABSTRACTThis CAREER award funds a project to image electron spins in complexmaterials. Although electrons in metals mind their own business, barelyinteracting with each other, in so-called 'strongly correlated electron'materials the interactions of electrons drive unique properties that arefascinating and often useful. For example, so-called high-Tcsuperconductors carry electricity without loss at economically feasibletemperatures; multi-ferroic materials allow electronic data storage usinga magnetic field and magnetic data storage using an electric field; heavyfermion materials boast electrons behaving with thousands of times theiractual mass; simple sheets of carbon called graphene allow electrons tozip along as if they had no mass at all. These materials have in commonthat their electrons interact strongly, and that those interactions arepoorly understood. This project will employ a spin-polarized scanningtunneling microscope to measure the energies and locations of electronspins with atomic resolution, starting with superconductors. The projectwill also use this technology to educate three deserving groups: Harvardstudents will benefit from a new undergraduate course on scanningtunneling microscopy; local elementary school children will be invited tosee a working science lab viewing real electrons; interested citizens willbe able to browse a colorful website explaining the fascinating variety ofmaterials under investigation.TECHNICAL ABSTRACTThis CAREER award funds a project to image electron spins in high-Tcsuperconductors, both cuprates and pnictides. The common feature to theseexotic materials is that their electrons interact strongly, and there isno broadly successful theoretical language to describe these so-called'correlated electron materials'. Great strides have been made throughvarious methods of imaging the interactions of electron charges, butunderstanding has been limited by the lack of effective tools to image theinteractions of electron spins. This project will employ a lowtemperature spin-polarized scanning tunneling microscope to measure thespin-resolved density of electronic states with atomic resolution. Inparticular, a comparison will be made between spin interactions incuprates and pnictides, the only two known families of high-Tcsuperconductors, discovered in 1986 and 2008. The project will also usethis spin imaging technology to educate three deserving groups: Harvardstudents will benefit from a new undergraduate course on scanningtunneling microscopy; local elementary school children will be invited tosee a working science lab imaging real electrons; interested citizens willbe able to browse a colorful website explaining the fascinating variety ofstrongly correlated materials under investigation.