Abstract
"Atomic-resolution holography [1]” is a powerful technique that realized an analysis of the local 3D atomic arrangement around not only constituent atoms in a crystal but also isolated atoms such as dopants. In photoelectron holography, the angular distribution of photoelectrons emitted from the target atom is used as a hologram, which can be used to directly derive the three-dimensional atomic arrangement around the emitter atom. Hologram requires at least ±60° cone angular distribution to reconstruct acurate 3D atomic arrangement with a kinetic energy of about 600 eV. DIANA [2] has been used to measure holograms effectively because it can display the angular distribution of ±60° at once. The energy resolution of DIANA is 1 %, which is insufficient to resolve chemical shift. Hence we are developing a new high-energy-resolution display analyzer CoDELMA [3, 4], which is shown in Fig. 1. CoDELMA is the only two-dimensional electron spectrometer that can display the angular distribution of particular high-energy electrons with a high-energy-resolution of ΔE/E = 1/500 over a wide two-dimensional angular range of ±50° at once.
The use of a synchrotron facility is another obstacle to the use of holography for routine analysis. Hence we are developing atom-holography microscope (Fig. 1) by a combination of a scanning electron microscope (SEM) and CoDELMA. This new microscope enables us to easily analyze the 3D atomic arrangement around specific atoms at each nano region observed by SEM in the laboratory. Recent results are shown in the presentation.
References:
[1] H. Daimon, Jpn. J. Appl. Phys. 59, 010504 (2020).
[2] H. Daimon, Rev. Sci. Instrum, 59 (4) 545-549 (1988).
[3] H. Matsuda, L. Tóth, and H. Daimon, Rev. Sci. Instrum. 89, 123105 (2018).
[4] H. Matsuda, H. Daimon, et al., J. Electr. Spectr. Rel. Phenom. 264, 147313 (2023).
