Zhu Xuetao, Cao Yanwei, Zhang Shuyuan, Jia Xun, Guo Qinlin, Yang Fang, Zhu Linfan, Zhang Jiandi, Plummer E W, Guo Jiandong
Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
Rev Sci Instrum. 2015 Aug;86(8):083902. doi: 10.1063/1.4928215.
High resolution electron energy loss spectroscopy (HREELS) is a powerful technique to probe vibrational and electronic excitations at surfaces. The dispersion relation of surface excitations, i.e., energy as a function of momentum, has in the past, been obtained by measuring the energy loss at a fixed angle (momentum) and then rotating sample, monochromator, or analyzer. Here, we introduce a new strategy for HREELS, utilizing a specially designed lens system with a double-cylindrical Ibach-type monochromator combined with a commercial VG Scienta hemispherical electron energy analyzer, which can simultaneously measure the energy and momentum of the scattered electrons. The new system possesses high angular resolution (<0.1°), detecting efficiency and sampling density. The capabilities of this system are demonstrated using Bi2Sr2CaCu2O(8+δ). The time required to obtain a complete dispersion spectrum is at least one order of magnitude shorter than conventional spectrometers, with improved momentum resolution and no loss in energy resolution.
高分辨率电子能量损失谱（HREELS）是一种用于探测表面振动和电子激发的强大技术。表面激发的色散关系，即能量作为动量的函数，过去是通过在固定角度（动量）测量能量损失，然后旋转样品、单色仪或分析器来获得的。在此，我们介绍一种用于HREELS的新策略，利用一个特别设计的透镜系统，该系统带有双圆柱形伊巴赫型单色仪，并与商业的VG Scienta半球形电子能量分析仪相结合，它可以同时测量散射电子的能量和动量。新系统具有高角分辨率（<0.1°）、探测效率和采样密度。使用Bi2Sr2CaCu2O(8+δ)证明了该系统的能力。获得完整色散谱所需的时间比传统光谱仪至少短一个数量级，同时动量分辨率得到提高且能量分辨率没有损失。
