University of Tokyo

报告人简介：

Prof. Yoshiya Uwatoko is an experimental physicist in the fields of high-pressure and strongly correlated electronic systems. He obtained his PhD from the Hiroshima University in 1988. After a three-year Research Associate in Kumamoto University and short-time Visiting Researcher in Los Alamos National Laboratory, USA, he joined the Saitama University as an Associate Professor in 1995. In 2001, he moved to the University of Tokyo as an Associate Professor and then was promoted as a full Professor in 2013. He now works in the Materials Design and Characterization Laboratory of the Institute for Solid State Physics, University of Tokyo.

Prof. Uwatoko is well known for his highly original discoveries in the effect of pressure on strongly correlated systems and the innovative development of high-pressure apparatus. He has published over 600 research papers, including Phys. Rev. Lett., Nat. Commun., Sci. Adv. etc, as well as 13 Books and Review Articles. He received the Rare Earth Society of Japan Award (Shiokawa Award) in 2020. He is the membership of Physical Society of Japan, the Japan Society of High Pressure Science and Technology, the Rare Earth Society of Japan, the Japanese Society for Neutron Science.

报告摘要：

Important external parameters that determine the state of matter are temperature, pressure and magnetic field. Research to control the states of matter using these parameters are being performed for a long time. In particular, research using high pressure as a tuning parameter has been fruitful in discovering emergent novel physical phenomena that have seldomly been predicted. In my talk, I will present our recent studies, on pressure-induced superconductivity in materials containing 4f rare-earth elements.

The binary compound CeZn, which exhibits a simple CsCl-type cubic structure at ambient pressure, undergoes multiple structural transitions under external pressure. To understand these pressure-induced multiple crystal phases, we systematically investigated the x-ray diffraction (XRD) measurements of CeZn in the pressure range up to 9.6 GPa. We have clarified that the cubic-tetragonal structural phase transition occurs at 2.2 GPa, and the tetragonal-orthorhombic structural phase transition occurs at 3.0 GPa. Furthermore, by utilizing the shortest Ce-Ce distance, as a parameter, we achieved a unified understanding of electronic states in these four crystal structures. The emergence of pressure-induced superconductivity is related to the monoclinic crystal structure implying a nonmagnetic origin of the Cooper pair formation. In addition, I will introduce various high-pressure devices developed for measurements of various physical properties of materials under good hydrostatic pressure conditions up to 20 GPa.

邀请人：程金光（8264 0765）

联系人：胡    颖（8264 9361）