Solid-state Information Physics Laboratory

Staff & Contact

Educational Staff	Prof. Tomohiro Matsushita Associate Prof. Ken Hattori Assistant Prof. Sakura Takeda Assistant Prof. Yusuke Hashimoto Assistant Prof. Takanobu Jujo Assistant Prof. Yuta Yamamoto
URL	https://mswebs.naist.jp/LABs/surface-material-physics/index.html

Education and Research Activities in the Laboratory

1.　Research purpose and target

Functional materials are created by adding dopant atoms to the material or depositing atoms on the surface. The added atoms in bulk work as active sites and dramatically change the material’s properties. Also slightly deposited atoms on surfaces can change structures and functionalities. Visualizing the three-dimensional atomic arrangement and understanding the function generation mechanism will bring about technological innovation. Our laboratory is the first in the world to develop photoelectron holography (PEH) to visualize dopant sites, and in developing apparatus in SPring-8. Our laboratory also studies surface structures, electronic states, and magnetism using scanning tunneling microscopy (STM), reflection high-energy electron diffraction (RHEED), low-energy electron diffraction (LEED), angle-resolved photoelectron spectroscopy (ARPES), cathode luminescence (CL), etc. For data science, we use a combination of scattering quantum mechanics, density functional theory (DFT), and artificial intelligence (AI). Our research targets include semiconductors, oxides, and alloys; atomically-controlled surfaces and nano-films/wires/dots, artificially designed 3D shaped structures, and nano-scale space charge layers. Our aim is to clarify the physical properties of active sites and modified surfaces, while creating new functions from atomic and electron viewpoints.

2.　Educational policy

We provide education on experiments and physics combined with informatics. Also, we aim to develop important skills for researchers and professional engineers, which include an active attitude toward obtaining knowledge through acquisition of technical expertise (such as shop practices, machine control, and data analysis), cooperation with laboratory members, finding essential points based on logical thinking, presenting ideas, and managing activities. Students are expected to improve or create apparatuses before graduation. It is important for students to not only learn how to think systematically through seminars and lectures, but also to interact with external researchers in addition to the regular laboratory educational staff.

Research Themes

Atomic structural analysis of active sites in/on materials by PEH
Quantum theory of scattering combined with AI
Creation of 3D Si structures with nano-films using lithography, STM, LEED, RHEED
Surface roughness analysis by RHEED
Electronic states of 3D-Si structures and semiconductor space charge layers by ARPES and AI
Surface defects by surface sensitive CL

Explanatory Pictures of Research Activities

Fig. 2 Atomic-scale STM image of ultra-thin film and island of iron-silicides on a Si(111) surface.

Fig. 3 3D-RSM of a 3D elongated island of α-FeSi₂(110) on Si(001).

Fig. 4 Si valence subbands in p-type inversion layer.

Recent Research Papers and Achievements

Y. Li, Y. Hashimoto, T. Matsushita et al., Sci. Rep., 15, 8366 (2025).
M. N. Fujii, M. Tanaka, T. Matsushita, et al., Nano Lett. 23, 1189 (2023).
T. Yokoya, T. Matsushita, et al., Nano Lett. 19, 5915 (2019).
H. Tanaka, K. Kuroda, T. Matsushita, J. Elec. Spec. Rel. Phenom. 264, 147927 (2023).
A. Irmikimov, K. Hattori, et al., ACS Cryst. Growth Des. 21, 946 (2021).
K. Hattori, Y. Sakai, L. N. Pamasi, et al., eJSSNT 20, 214 (2022).
N. I. Ayob, T. J. Inagaki, H. Daimon, S. N. Takeda, Jpn. Appl. Phys. 60, 064004-1 (2021).