東京大学新領域創成科学研究科基盤系物質系専攻| Kaoru Kimura-Lab

INTRODUCTION OF LABORATORY

Chemistry of group-13 elements Group-13 elements such as B and Al are the rare elements that form icosahedral cluster structures. We found that the character of such clusters in solids can be converted from covalent to metallic, by introduction of central atoms. By using an electrostatic levitation system, we discovered that liquid boron is a semiconductor. Searches for new cluster superconductors and new cluster molecules are in progress, from calculation and experiments. Quasicrystals Quasicrystal are lattice structures that lacks periodic symmetry, like a Penrose lattice with 5-fold symmetry. We are searching for new three-dimensional quasicrystals that contains icosahedral clusters of group 13-elements. We investigate the properties of those quasicrystals and related structures (approximant crystals) from theory and experiments. The final goal of us is the first discovery of semiconducting quasicrystals. Search for new thermoelectric materials Thermoelectric materials are solids that convert heat and electricity. However, determination of the most promising material family is difficult, since thermoelectric properties changes dramatically by varying carrier density, impurity doping and microstructures. By first-principles calculations and experiments, we are investigating thermoelectric properties of various complex intermetallic compounds including quasicrystals and incommensurate compounds. We succeeded in discovery of new thermoelectric materials RuGa2 and FeGeγ. By collaboration with information scientists, we are gathering a big data of experiments in past literatures, and applying machine learning techniques to accelerate research and development

ボロン系とアルミ系正20面体クラスター固体の多重殻構造の比較アルミ系では、共有結合を持つボロン系で空になっているサイト（点線の円）に原子が存在し金属結合となっている

Message

IMPRESSION IN THE AGE OF TWENTIES IS ENTIRE LIFE’S TREASURE IN THE FIELD OF SCIENCE.

The discovery of "Quasicrystal" gave a great impression to me, and I have continued to investigate it until now. It takes 27 years from the first discovery in 1984 to get Novel Prize in 2011 after establishment as a big concept of solid state structure, which takes a place beside "Crystal" and "Amorphous". In "Quasicrystal", "Semiconductor" and "Insulator" have not yet been discovered. It is remaining as a basic problem in the solid state physics, whether they exist or not. On the other hand, the development of high performance "thermoelectric material" has a potential to be a key technology, which can contribute to the energy problem and the environmental one. We are proposing that "Semiconducting Quasicrystal" should be a great candidate for thermoelectric material.

MEMBER

Professor Kaoru Kimura

1979 Graduation, Department of Physics, the University of Tokyo

1984 PhD, Department of Physics, the University of Tokyo

1984 Research associate, Institute for Solid State Physics, the University of Tokyo

1989 Lecturer, Department of Materials Science, the University of Tokyo

1992 Associate professor, Department of Materials Science, the University of Tokyo

1993-1994 Visiting researcher, Gerhardt Mercator University, Duisburg, Germany

1994 Associate professor, Department of Materials Engineering, the University of Tokyo

1999 Professor, Department of Advanced Material Science, the University of Tokyo

STUDENT VOICE

Koichi Kitahara

Professor Kimura is a mild parson. Because he is respecting self-initiative of students, we can determine many things by ourselves in our research activity. He supervises us to give a definite comment from the wide view based on his experience. We think that he is an ideal professor for self-active students. In our laboratory, we are doing material development and basic evaluation based on the view of applied solid state physics (nano-space function design). Because there are calm atmosphere in our laboratory, it is easy to ask and discuss many things. We, laboratory members, are absorbing knowledge and technique each other, as a result, we can focus on the most important point of the research theme.