Materials structure physics

In the Materials Structure Science Program, we are investigating the static structure of materials by means of precise X-ray crystal structural analysis, resonant X-ray scattering, magnetic X-ray scattering, and X-ray imaging. In addition, we are studying the dynamic structure of materials via a pump-and-probe experiment that uses a synchrotron radiation pulse. Our research has expanded from fundamental high-pressure properties to Earth and planetary science by a combination of high-pressure X-ray measurements. In addition to our research, we are optimizing beamlines and experimental devices to promote our research and are developing research methods that use the next-generation light source.

● Main research projects

Elucidation of the mechanism of property expression using accurate structural analysis

We are studying how the arrangement of atoms, ions, and molecules in crystals contributes to property expression. In addition, we are studying the relationship between changes in the crystal structure and the physical properties of crystals when external perturbation, such as temperature, electric field, pressure, or photoirradiation, is added.

We discovered a new type of magnetic ordered phase in iron-based superconductors.
We found the vitreous state of electrons.
We demonstrated a new principle in the expression of electric polarization by using an organic ferroelectric.
We created a new technique of film-making by coating a semiconductor onto a surface that strongly sheds liquid.

External electric field and ion displacement in an "electronic ferroelectric" TTF-CA.(電場: Electric field, 変位: Displacement, 電子移動: Electron transfer)

Novel ordered phases as a stage of interesting physical properties

In materials science, novel ordered phases related to new physical properties are often found. Such phases are not only interesting as fundamental physics but are very important to understand the origin of physical property.

To elucidate the existence of the "intermediate spin state" in cobalt oxides
To fabricate new magnetic materials by controlling lattice strain with thinning

Various novel ordered structures: orbital and spin-state ordering.

Study of physical properties under extreme conditions from high-pressure X-ray composite measurements and the inner structure of the Earth and planets

Using X-ray diffraction and composite measurements from a combination of absorption spectroscopy, transmission imaging, and Mössbauer scattering, we are studying extraordinary crystal structures and physical properties under extreme conditions created by using a very high-pressure apparatus, a cryogenic device, and a laser-heating device. The aim of these wide-ranging studies is:

To elucidate various structures of gas hydrates
To elucidate structure of silica glass deep in the Earth
To study inner structures of Jupiter and Pluto, which are made of water and gas
To elucidate structure and viscosity of magma in the Earth
To elucidate driving mechanism of mantle convection
To study behavior of iron in the Earth's core and lower mantle
To study ultrahigh temperature and high-pressure synthesis of functional materials such as oxide superconductors and metal nitrides
To study the structural stability of basic elements and compounds under ultrahigh pressure

Materials science explored by X-ray imaging

We are developing various imaging systems to perform highly sensitive and highly accurate non destructive observations of the inner structures of electronic materials such as electronic devices. We hope to improve the performance of electronic devices by elucidating defects and strain fields in a sample by means of imaging. We are also developing an X-ray imaging method that can identify elements with high sensitivity.

(Left) Optical devices: development of a phase retarder. (Right) IC tag reconstructed 3D image in a pearl nucleus.

Capturing photoinduced modifications in the structure and electronic state by a molecular movie

We are researching photoinduced modifications in the structure and electronic state by a molecular movie in optical functional materials, artificial photosynthesis systems, photocatalysts, and photoreactive proteins, and we are studying the mechanisms of the generation of those optical functions. We hope to develop new light energy conversion materials and ultrafast switching devices.

The generation of a hidden phase in the photoinduced phase transition.

Cooperative structural change in the photoreactive protein.

Photoinduced molecular magnetism and associated molecular structural modification.

Members

Name	Position	Field
NAKAO, Hironori	Assoc. Professor	Condensed matter
KUMAI, Reiji	Professor	Condensed matter
FUNAMORI, Nobumasa	Professor	High pressure science
ADACHI, Shinichi	Professor	Structural biology
KISHIMOTO, Shunji	Professor (KEK)	X-ray detector
HIRANO, Keiichi	Assoc. Professor	X-ray imaging
NOZAWA, Shunsuke	Assoc. Professor	Ultrafast Structural dynamics
SAGAYAMA, Hajime	Assoc. Professor	Condensed matter
OKUYAMA, Daisuke	Assoc. Professor	Magnetism, Crystal/magnetic structure analysis
IWANO, Kaoru	Assoc. Professor	Theory on condensed matter
SUGIYAMA, Hiroshi	Assistant Prof.	X-ray imaging
WAKABAYASHI, Daisuke	Assistant Prof.	High pressure geoscience
SHIBAZAKI, Yuki	Assistant Prof.	High pressure science
ICHIYANAGI, Kouhei	Researcher (KEK)

● Beamlines in charge

X-ray crystal structure analysis/apparatus under extreaml conditions

BL-8A, BL-8B, BL-7C

High precision powder diffraction

BL-4B2

X-ray diffraction/scattering/detector development

BL-10A, BL-14A

X-ray diffraction experimental station

BL-3A, BL-4C, BL-6C, BL-18B

White X-ray magnetic diffraction experiments/X-ray optics

BL-3C

High pressure X-ray diffraction stations

BL-18C, AR-NE1A, AR-NE5C, AR-NE7A

A time-resolved X-ray station

AR-NW14A

X-ray imaging

BL-3C, BL-7C, BL-14B, BL-20B, AR-NE7A

● Links

Condensed Matter Research Center https://www2.kek.jp/imss/cmrc/english/index_eng.html

Instrument R&D Team http://pfwww.kek.jp/KeisokuSystem/(Japanese only)

Synchrotron Radiation