Study on electronic structure of itinerant ferromagnetic Mn pnictides by spin and angle resolved photoemission and inverse photoemission spectroscopies

这项研究的主要目的是发展配备紧凑型自旋偏振器和自旋极化电子枪的自旋和角度分辨光电子能谱和逆光电子能谱系统。这些系统将与广岛同步辐射中心的波荡器光束线连接。最终的目标是利用该系统研究巡回铁磁性锰离子的自旋相关电子态。在本财政年度，我们已经完成了自旋极化光电子能谱系统的性能测试。本财年，我们设计并制造了自旋极化电子枪。最后对电子枪的电子传输特性和能量分辨率进行了测量。由于反向光电子发射过程的效率与光电子发射过程相比很低，因此必须注意光电子源和电子枪的以下特性：1)来自GaAs阴极表面的稳定和大量的光电流；2)电子枪的高透射率。从GaAs源获得的光电流为10μA，最大阴极寿命为46小时。我们设计并制造了具有7个柱面透镜元件和90度柱面偏转器的电子枪。测得的电子透过率估计为41%。以上结果表明，本系统适用于SPIPES的测量。

The main purpose of this research is to develop the spin- and angle- resolved photoemission and inverse photoemission spectroscopy systems equipped with the compact spin polarimeter and the spin polarized electron gun. The systems will be connected with the undulator beamline in Hiroshima Synchrotron Radiation Center. The final goal is to investigate the spin dependent electronic states of itinerant ferromagnetic manganese pnictides using this system.In this fiscal year, we have finished the performance test for the spin polarized photoemission spectroscopy systems. We have designed and constructed the spin-polarized electron gun this fiscal year. Finally we have measured the electron transmission property and the energy resolution of the electron gun. Since the efficiency of inverse photoemission process is quite low compared to the photoemission process, it is important to take care of the following properties in regard to the photoelectron source and the electron gun.1) Stable and large amount of photocurrent from the NEA surface of GaAs cathode.2) High transmission property of the electron gun.The photocurrent of 10μA from GaAs and maximum cathode lifetime of 46 hours have been achieved. We have designed and constructed the electron gun with 7 cylindrical lens elements and 90 degrees cylindrical deflector. The measured electron transmission is estimated to be 41%. The above results show that our system is suitable for the measurement of SPIPES.