Milli-Electron Volt Energy Resolution Photoemission Studies of Solids

将在最近建造的仪器上进行低温下固体的极高能量分辨率(在1 kHz的计数速率下低于5 meV)的光电子发射研究。这些参数是对以前发表的固体样品工作的重大改进，并允许光电子能谱与其他研究能量为KT级的激发的实验方法相联系。提出了几个具体的实验：将研究电子-声子相互作用对角积分光谱中费米边的影响，以及在铜等宽带金属中小结合能时对单个表面态色散的影响；这将提供关于固体表面上和附近电子和声子相互作用的详细信息。研究硅中磷施主能级在金属/绝缘体临界浓度附近的浓度范围内的发射将确定单电子态密度，并有助于理解在驱动这一转变过程中关联和无序之间的竞争。对常规超导体和高温超导体的发射(峰色散和线形)和带隙的研究将有助于确定这些材料的超导机制。这项研究的目的是利用新开发的高分辨率光电子能谱仪的能力和辨别能力来解决当前材料物理中的一些问题。改进后的分辨率可能会对超导和半导体器件操作等技术领域以及更基本的各种相关领域产生强烈影响。这项研究将把光电子能谱的能量分辨率扩展约一个数量级，使人们能够详细研究负责设备操作的电子。特别是，半导体中的金属/绝缘体转变，高温和常规超导体中能隙的来源，以及更普通材料中电子和原子振动的相互作用将被研究。

Very high energy resolution (less than 5meV at count rates of 1kHz) photoemission studies of solids at low temperatures will be undertaken on a recently built instrument. These parameters are a significant improvement over previously published work on solid samples, and allows photoelectron spectroscopy to make contact with other experimental methods that study excitations with energies of order kT. Several specific experiments are proposed: Studies of the effects of the electron-phonon interaction on Fermi edges in angle integrated spectra, and on individual surface state dispersion at small binding energy in wide band metals such as copper will be undertaken; this will yield detailed information about the interaction between electrons and phonons at and near solid surfaces. Studies of emission from phosphorus donor levels in silicon for concentration ranges near the metal/insulator critical concentration will determine the one electron density of states and aid in understanding the competition between correlation and disorder in driving this transition. Studies of emission (peak dispersion and line shape) and of the band-gap in conventional and high temperature superconductors will help to determine the mechanism of superconductivity in these materials. %%% The purpose of this research is to bring the power and discrimination of a newly developed high resolution photoelectron spectrometer to bear on a number of current problems in materials physics. The improved resolution could impinge strongly on technological fields such as superconductivity and semiconductor device operation, as well as in various related areas of more fundamental interest. This research will extend the energy resolution of photoelectron spectroscopy by about an order of magnitude, permitting detailed studies of the electrons responsible for device operation. In particular, metal/insulator transitions in semiconductors, the origin of the energy gap in high temperature and conventional superconductors, and the interaction between electrons and atomic vibrations in more ordinary materials will be investigated.