Performance of a photoelectron momentum microscope at TPS 27A2 in direct- and momentum-space imaging using ultraviolet photon sources
Tzu-Hung Chuang1*, Chuan-Che Hsu1, Wei-Sheng Chiu2, Jyun-Syong Jhuang1, I-Chun Yeh3, Ruei-San Chen2, Shanjr Gwo1,3, Der-Hsin Wei1,4
1Scientific Research Division, National Synchrotron Radiation Research Center, Hsinchu, Taiwan
2Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei, Taiwan
3Department of Physics, National Tsing-Hua University, Hsinchu, Taiwan
4Department of Physics, National Sun Yat-sen University, Kaohsiung, Taiwan
* Presenter:Tzu-Hung Chuang, email:chuang.th@nsrrc.org.tw
The photoelectron-related image and nano-spectroscopy (PRINS) end-station located at the Taiwan Photon Source (TPS) 27A2 houses a photoelectron momentum microscope (MM) capable of performing direct-space imaging, momentum-space imaging, and photoemission spectroscopy with position sensitivity [1]. Offline commissioning was initiated in 2022.
In this report, we demonstrate the performance of this microscope using two in-house photon sources, an Hg lamp and He(I) radiation, on a standard checkerboard-patterned specimen and an Au(111) single crystal, respectively. By analyzing the intensity profile of the edge of the Au patterns, the Rashba-splitting of Au(111) Shockley surface state at 300 K, and the photoelectron intensity across the Fermi-edge at 80 K, the spatial, momentum, and energy resolution were estimated to be 50 nm, 0.0172 Å-1 and 26 meV, respectively [2]. Additionally, we show that the band structures acquired in either constant energy contour mode or momentum-resolved photoemission spectroscopy mode were in close agreement, and both modes can be performed in the same instrument.
In future, we would like to explore the capability of the microscope using a soft X-ray regime covered by the TPS 27A Soft X-ray Nanoscopy beamline. Perspectives on the future capabilities, including imaging based on X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS), and X-ray magnetic circular dichroism (XMCD) will be also presented.
References:
[1] Shiu, Chuang, et. al., Journal of Electron Spectroscopy and Related Phenomena 266, 147363 (2023).
[2] Chuang, et. al. (submitted)


Keywords: momentum microscope, Fermi contour, PEEM, ARPES, momentum-space