110th CEMS Colloquium


Prof. Takafumi Sato (Tohoku University)


17:30 - 18:30, March 22, 2023 (Wednesday)


Okochi-Hall, RIKEN


Spatially resolved electronic structure of novel topological materials


Electronic band structure characterizes physical properties of crystalline solids. Angle-resolved photoemission spectroscopy (ARPES) is a simple experimental technique based on the well-known external photoelectric effect, and has established as a standard experimental technique to elucidate band structure of quantum materials such as high-temperature superconductors and topological insulators. Recent progress in the spin- and time-resolved ARPES techniques further enables us to clarify electron dynamics and spin-dependent band structure of various functional materials. Currently, spatially resolved ARPES is attracting great deal of attention because it is highly useful to access electronic states of even wider materials and devices which are hard to be accessed by the conventional techniques [1].

In this talk, I will overview recent progress of spatially resolved ARPES [1,2], by highlighting key experimental results such as the band-structure characterization of hard-to-cleave crystals [3] and tiny powder samples [4]. Identification of various types of domains at the surface (e.g., polar domain and magnetic domain) plays an essential role to pin down the mechanism of unconventional physical properties such as charge order and superconductivity in kagome-lattice compounds [5-7] and antiferromagnetic topological-insulator phase in rare-earth monopnictides [8]. I will also discuss how the spatially resolved ARPES technique can be incorporated into the investigation of quantum materials, by putting emphasis on the use of next generation synchrotron “NanoTerasu”.

[1] H. Zhang et al., Nature Reviews Methods Primers 2, 54 (2022)
[2] M. Kitamura et al., Rev. Sci. Instrum. 93, 033906 (2022)
[3] C.-W. Chuang et al., Phys. Rev. Mater. 6, 104203 (2022)
[4] K. Sugawara et al., Nano Lett., in press (2023)
[5] K. Nakayama et al., Phys. Rev. B 104, L161112 (2021)
[6] K. Nakayama et al., Phys. Rev. X 12, 011001 (2022)
[7] T. Kato et al., Phys. Rev. Lett. 129, 206402 (2022)
[8] A. Honma et al., submitted.