High Resolution Inverse Photoemission System with Polarization Analysis

具有偏振分析功能的高分辨率逆光电发射系统

基本信息

批准号：
04559008
负责人：
SUGA Shigemasa
金额：
$ 11.9万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research (B)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1994
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-04559008/
关键词：
IPES VUV Spin polarization NEA Cathode High Resolution Unoccupied State vuv 逆光電子分光 BIS 高分解能電子レンズ LEED フェルミ準位角度分解逆光電子

项目摘要

The inverse photomission(IPES) spectroscopy with capabilities of polarization analysis and very high resolution is strongly required to probe the electronic states very near the Fermi level. A system which satisfies such requirements is developed and partly tested. The high energy resolution of the band pass detector is realized by use of the difference spectrum between two IPES spectra measured with a SrF_2 low pass filter set at two different temperatures. The energy shift of the Urbach tail due to the excitonic absorption edge enables one to measure the IPES spectrum with different band pass characteristics. So the difference spectrum realizes a resolution better than 0.25 eV.The energy band width of the excitation electron beam can be reduced by use of the negative electron affinity(NEA) GaAs cathode with use of Cs and O_2 deposition. For this purpose, not only an in-vacuum Ar bombard cleaning but also a preceding chemical cleaning is very important. In order to realize a good vacuum for NEA cathode, we installed NEG(non evaporating getter pump) and a high pumping speed ion pump. The transmittance of the electron lens is improved up to 50-80%. We finally got photoelectron current of more than 10 A with a life time of more than 10 hours.In addition, 3 grids LEED(low energy electron diffraction) and Auger optics are installed. Pulse magnet system to magnetize ferromagnetic samples is also developed. This is used to measure the polarization dependence spectrum of ferromagntic materials.

具有极化分析能力和非常高分辨率的能力的逆光发射（IP）光谱很强，以探测非常接近费米水平的电子状态。满足此类要求的系统将得到开发和部分测试。通过在两个不同温度下使用SRF_2低通滤波器集测量的两个IP频谱之间的差异光谱之间的差异光谱之间的差异光谱通过使用差异来实现。由于激光吸收边缘而引起的urbach尾巴的能量移动使一个人能够以不同的带传特性来测量IPES频谱。因此，差异光谱实现了比0.25 eV更好的分辨率。通过使用CS和O_2沉积，可以使用负电子亲和力（NEA）GAAS阴极来减少激发电子束的能带宽度。为此，不仅可以进行爆炸式轰炸机清洁，而且在上面的化学清洁工作也非常重要。为了实现NEA阴极的良好真空，我们安装了NEG（非蒸发Getter Pump）和高泵浦速度离子泵。电子镜头的透射率提高了50-80％。我们终于获得了超过10个小时以上的10 a的光电子电流。此外，安装了3个网格LEED（低能电子衍射），并安装了螺旋钻的光学。还开发了脉冲磁铁系统来磁化铁磁样品。这用于测量铁磁材料的极化依赖谱。