Spin-resolved momentum microscope at Taiwan Photon Source

Der-Hsin Wei a, Tzu-Hung Chuang a, Chuan-Che Hsu a, Jyun-Syong Jhuang a, I-Chun Yeh a,b, Wei-Sheng Chiu a,c,

Wei-Ting Hsu b, Shangjr Gwo a,b, and Chih-Kang Shih b,d

a National Synchrotron Radiation Research Center, Taiwan

b Department of Physics, National Tsing Hua University, Taiwan

c Graduate Institute of Applied Since and Technology, National Taiwan University of Science and Technology, Taiwan

d Department of Physics, the University of Texas at Austin, USA

Generation and manipulation of spin-polarized carriers play key roles in spintronic applications, yet their optimization can hardly be realized without the knowledge of electronic structures (in momentum space, k-space) and magnetic microstructures (in real space, r-space) of materials in use. In this talk, I will describe how the needed information mentioned above can be unraveled by the momentum microscope established recently at Taiwan Photon Source (TPS) Nano-Spectroscopy beamline 27A2. An intriguing feature of the momentum microscope at TPS 27A2 is its option to record images in either r-space or k-space with simply a switch that changes the settings of electron lenses. Such a feature implies that there is no more hassle in examining the electronic structures from the very same micro-meter spot of the specimen. On top of that, this momentum microscope is equipped with a spin mirror to provide spin-resolved images. Because the electron reflectivity from an Ir(001) surface is a function of an electron’s energy and spin, the images recorded with reflected electrons under constant-energy mode are thus spin-resolved. Performance of the momentum microscope at TPS 27A2 is to be demonstrated with the real space images of an Au/Si chessy pattern, the constant energy contour of a single flake of two-dimensional (2D) material, and the spin-resolved Shockley surface state on Au(111) surface.