[No. 122] Tetsuya Morishita

I am honored to have this opportunity to write for the Alumni Relay Column. I spent nine years at Keio University, from my undergraduate studies through my master's and doctoral degrees. Even now, my work at the National Institute of Advanced Industrial Science and Technology (AIST) allows me to directly apply what I learned at Keio. I would like to take this opportunity to briefly look back on my time from Keio to the present.

From the time I entered university, I was already thinking about advancing to the Department of Physics. For that reason, I studied reasonably hard in the required and elective courses in physics, chemistry, and mathematics, but I remember struggling quite a bit to earn credits in language and general education courses. I took French as my second foreign language, but in the end, I never really understood it. However, the instructors were a group of unique individuals, and the French classes themselves were quite interesting. I've forgotten the content, but there were times when an entire class period ended with the instructor's amusing small talk.

I joined a chamber music club that played baroque music, so during my free time between classes, I often hung out in the club room at the Student Union Building. I played the violin, and we often performed in ensembles of about three to ten people, incorporating a variety of instruments like the viola, cello, flute, and recorder. We held regular concerts twice a year, so just before a concert, we would practice frequently in the "onren" (music practice rooms) in the basement of the Student Union Building, from around 6:00 p.m. when classes ended until the building closed at 9:00 p.m. Normally, we practiced every Saturday in a room we borrowed from a kindergarten in the Namamugi area. I remember returning to Hiyoshi after practice and often going for drinks in "Hiyoura." Fortunately, there were many upperclassmen from the Faculty of Science and Technology in the club, so I could easily get my hands on past exam papers. I was also able to get information about various professors in the Faculty of Science and Technology, which was a great help when selecting courses for promotion to the next year. The club's activities were quite substantial, with two concerts and three training camps a year, so I was able to spend a lot of enjoyable time with many upperclassmen and underclassmen. We are still in touch today, and looking back, I think it was a time when I was able to have a very valuable life experience. As the club was the center of my life during my undergraduate years, I continued to show up at the Student Union Building and practice hard even after I started commuting to the Yagami Campus.

I was able to advance to the Department of Physics upon promotion from my second year, and for my fourth-year laboratory assignment, I was able to join the theoretical research laboratory as I had hoped. At that time, life in the theoretical physics lab for fourth-year students consisted only of seminars in the first semester, so I didn't have much opportunity to experience what a university laboratory was like. Once my graduation research began in the second semester, I started going in and out of the lab more often, but I recall that as a fourth-year student, I was never assigned my own desk in the lab. After graduation, I proceeded to the master's program and then to the Doctoral Programs, obtaining my degree for research on crystal structures using molecular dynamics simulations. This was a theme related to my fourth-year graduation research, and ultimately, the research theme from my fourth year determined the direction of my future path. In fact, I was supervised by the late Professor Shuichi Nose, who guided my graduation research in my fourth year, all the way through to obtaining my doctoral degree.

After obtaining my doctorate, I conducted research as a postdoctoral fellow for three years at RIKEN in a position called Special Postdoctoral Researcher. Immediately after finishing the Doctoral Programs at Yagami, I became interested in the research on liquids being conducted in the experimental laboratories of the Department of Physics. Therefore, at RIKEN, I made liquids my main research subject, instead of the crystals I had studied during my graduate school years. In a liquid, atoms may seem to exist randomly, but in a very confined space, a certain degree of regularity can be found in their arrangement. By performing molecular dynamics simulations, which are atomic-level simulations, I succeeded in predicting the pressure and temperature dependence of such atomic arrangement structures in liquids.

After spending three years at RIKEN, I went through the University of Tokyo and then joined my current employer, the National Institute of Advanced Industrial Science and Technology (AIST). My earlier research on liquids further evolved to include glass as a subject. In recent years, I have also been predicting the behavior of nanoscale materials using molecular dynamics simulations. I am particularly focused on two-dimensional structured materials of silicon, and recently, we have revealed that a certain silicon material with a 2D nanoscale structure can be applied as a new material for secondary battery electrodes and field-effect transistors. In this way, it is becoming possible to discover new properties of materials through simulation, and this is attracting attention from the industrial sector. In the future, I intend to focus on the further development of simulation algorithms and computational theories to make such computer-based material design commonplace.

Fortunately (?), I have been able to continue my research in condensed matter physics as my profession ever since my graduate school days. I believe this is thanks to the guidance of the professors in the Department of Physics, especially the late Professor Shuichi Nose, who passed away at a young age. If you ask whether I made any particular effort myself, there is not much I can say with pride. However, there may have been an element of "what one likes, one will do well." It may be difficult in this day and age to continuously focus on one thing, but if it is something you love, I believe you will surely gain something by continuing, even if other work is demanding. I also intend to further continue my research and devote myself to the study of molecular dynamics in the future.

Finally, I would like to express my gratitude to Professor Takano and Professor Watanabe for giving me the opportunity to write for the Alumni Relay Column.