Career Summary
1979: Graduated, Department of Physics, Faculty of Science, The University of Tokyo
1984: Selected for a Research Fellowship for Young Scientists of the Japan Society for the Promotion of Science
1984: Research Associate, The Institute for Solid State Physics, The University of Tokyo
1985: Doctor of Science from 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
1983-84: Visiting Researcher, Gerhardt Mercator University of Duisburg, Germany
1999: Professor, Department of Advanced Materials Science, The University of Tokyo
Educational Activities
Graduate school:Cluster Function Design, Advanced Materials Science I
Faculty of Engineering: Materials Physics II, Physical Properties of Materials I
Research Activities
Professor Kimura has been studying the structure and properties of solids with complex structures, such as amorphous solids, quasicrystals, and giant unit cell crystals.
Solids with complex structures are considered to be nanoscale composit materials having properties and functions that cannot coexist in a solid with a simple structure.
This area of study is an trial of academic fusion, in which two fields of study, i.e., metals and semiconductors, are integrated, and has been progressing towards the development of an intermediate material between metals and semiconductors.
In 1981, Professor Kimura experimentally demonstrated the equivalence of two phenomena based on nonequilibrium, which is the nature of amorphous solids: 1) structural change accompanying the glass transition and 2) photostructural change in chalcogenide glasses.
This marked the beginning of the study of electron-excited atomic migration, a field which has recently emerged.
Immediately after the discovery of an aluminum-based quasicrystalline alloy in 1984, Professor Kimura started the study of this field.
In particular, in 1989, he demonstrated that the aluminum-based quasicrystalline alloy had an extraordinarily high electrical resistivity.
Such a high electrical resistivity defied conventional understanding on the resistivity of alloys.
Furthermore, he found that with a low state density (a pseudogap) at the Fermi level and the localization of the electronic states are behind the high resistivity (Reference 1).
On the basis of this accomplishment, he won the 8th Science Prize of IBM Japan in 1994.
Since then, he has experimentally clarified semiconductor properties and the existence of covalent bonds in the quasicrystalline alloys.
His study has led to an understanding of the relationship between a mechanism based on long-range order and covalent bonds based on short-range order.
Since 1989, he has been expanding his fields of study to boron-rich semiconductors, which consist mainly of group III boron (the same group as aluminum, which is the main component of the quasicrystalline alloys with a high electrical resistivity) and have an icosahedral cluster structural unit.
On the basis of research achievements in this field, he was awarded the 13th Murakami Young Researcher Award in 1993.
In addition, he discovered an approximant of quasicrystal in a boron-carbon-based system, and received the Jeffries Award from The Japan Institute of Metals.
He also clarified the properties of icosahedral cluster solids of boron by comparing them with fullerene solids and silicon clathrate compounds.
Thanks to the recent discovery of the high superconductor transition temperature (Tc) of MgB2 by the other researchers, Professor Kimura's research results are contributing to the search for superconductors having a much higher Tc.
In 1997, Professor Kimura discovered a "metallic-covalent bonding conversion" due to slight structural changes in the boron and aluminum icosahedral clusters, and has been experimentally demonstrating this conversion.
By discussing the properties of both the aluminum-based quasicrystalline alloys and the boron-based semiconductors, which conventionally have been discussed separately in the fields of metals and semiconductors, he has been successful in constructing a unified picture of icosahedral cluster solids (Reference 2).
This is an example of academic fusion.
In recognition of his outstanding achievements, he was conferred the Meritorious Award from The Japan Institute of Metals in 2002.
He is currently involved in evaluating this group of materials as an intermediate material between metals and semiconductors and as solids with a complex structure (nanoscale composit material), to develop thermoelectric conversion materials and high-resistance chip materials.
In 1997, 2000 and 2003, he discovered the growth of BN nanotubes and nanocones by heat treatment of BN in Li vapor, and boron nanobelts by pulsed laser deposition of pure boron, respectively, and began research on nanostructures such as nanotubes, nanowires and clusters isolated in space.
Literature
1) K. Kimura and S. Takeuchi, in QUASICRYSTALS: THE STATE OF THE ART (2nd Edition), ed. D. P. Divincezo and P. J. Steinhardt, World Scientific, Singapore, 325-359 (1999).
2) K. Kimura et al., J. Solid State Chem. 133, 302-309 (1997).
Other Activities
The Japan Institute of Metals (Board member, Editorial member of Japanese and English journals, Editorial member of newsletter, Member of sectional committee)
The Physical Society of Japan (Facilitator of semiconductor sectional committee, Facilitator of metal sectional committee)
Workshop of Thermoelectric Conversion (Steering committee, Manager, Chef Editor of the English journal)
The International Symposium on Boron, Borides and Related Compounds (International Scientific Committee Member)
Materials Research Society (MRS)
Japan MRS (MRS-J)
Society of Nano Science and Technology
The fullerenes and Nanotubes Research Society
Future Plan
A solid with the dimensions of approximately 1 cm3 is a super-multibody system composed of approximately 10 to the 23rd atoms.
In this field of study, many freedoms still remain in terms of themes yet unexplored by conventional pure solid-state physics.
The mission for researchers in the field of Advanced Materials Science is to probe this degree of unexplored freedom and to develop new concepts and future visions, as well as to develop their applications.
As one approach, Professor Kimura aims to develop a concept of cluster solids for the purpose of understanding material functions and exploring new materials.
A concrete example is the icosahedral cluster solid described above, which is a fruit of the academic fusion that the graduate school, as a whole, is aiming for.
Messages to Students
I hope that graduate students can cultivate their flexibility and potential to carve their own path for any research theme related to materials science and technology they may encounter.
"A frog in a well knows not the ocean yet knows the depth of heaven."
In a limited world, i.e., the university, .......
