Condensed Matter Experiment I
Strongly Correlated Electron Physics
Academic Staff
- Adjunct Professor／Kenji Ishii
- Guest Professor／Yo Tokunaga
- Guest Professor／Kazunari Yamaura
About Research
Strongly Correlated Electron Physics Group consists of three guest professors belonging to national and independent research institutes. Research topics of each group are as follows.
Yo Tokunaga (Japan Atomic Energy Agency, JAEA)
URL: https://asrc.jaea.go.jp/asr_eng/
Since the discovery of superconductivity in 1911, many types of superconductors have been found, including cuprates, organic materials, and iron-based compounds. These discoveries have revealed the diverse properties of superconductors. In particular, since the 2000s, a new type of superconductivity called “spin-triplet superconductivity” has been discovered in uranium-based compounds. This has attracted significant attention due to its unusual properties. For example, surprising phenomena have been observed, such as the microscopic coexistence of ferromagnetism and superconductivity. Additionally, in some cases, superconductivity is enhanced rather than weakened when a magnetic field is applied.
Spin-triplet superconductors are also expected to function as topological superconductors, which may be useful for next-generation quantum computers. Our research group employs various experimental techniques, including nuclear magnetic resonance (NMR), single-crystal growth, magnetic and transport measurements, and neutron scattering, to study new and intriguing properties of strongly correlated electron systems. We also utilize microfabrication techniques for single crystals in these studies.
Kazunari Yamaura, (National Institute for Materials Science, NIMS)
URL: https://www.nims.go.jp/eng/index.html
Dr. Kazunari Yamaura specializes in the development of exchange bias materials and their applications in spintronics, particularly in strongly correlated electron systems. His research focuses on designing bulk materials that exhibit exchange bias effects without relying on artificial interfaces, exploring double perovskite compounds to achieve this goal. Using high-temperature and high-pressure synthesis equipment at NIMS, he synthesizes novel materials and evaluates their structural properties through high-resolution X-ray diffraction measurements at the synchrotron radiation beamline at SPring-8. Additionally, first-principles calculations are employed to analyze the underlying mechanisms governing these properties, integrating both theoretical and experimental approaches to material design. Dr. Yamaura leverages NIMS’s state-of-the-art facilities and collaborates internationally with institutions such as ORNL and ISIS to conduct neutron diffraction experiments for magnetic structure analysis. Through these studies, he aims to elucidate the effects of magnetic anisotropy and electron correlation in strongly correlated systems, contributing to the development of next-generation functional materials.
Adjunct Professor(National Institutes for Quantum Science and Technology, QST)
URL：https://www.qst.go.jp/site/kansai-english/
Our research focuses on strongly correlated electron systems using intense synchrotron X-rays generated at world-leading synchrotron radiation facilities such as NanoTerasu, located on the Tohoku University campus, and SPring-8 in Hyogo Prefecture, Japan. In strongly correlated electron systems, including transition-metal compounds, physical properties emerge from the intricate interplay among the charge, spin, and orbital degrees of freedom of electrons, as well as the crystal lattice. Advanced synchrotron X-ray techniques provide unique insights that are difficult or impossible to obtain using conventional experimental methods, making them powerful tools for disentangling these complex interactions. For example, resonant inelastic X-ray scattering (RIXS), one of the most advanced synchrotron-based spectroscopies, enables direct observation of excitations associated with charge, spin, orbital, and lattice degrees of freedom. By probing these excitations, we can reveal the interactions that govern their dynamics and ultimately determine the macroscopic properties of materials. Our goal is not only to develop and advance synchrotron-based experimental techniques for elucidating the mechanisms underlying emergent phenomena in strongly correlated electron systems, but also to apply the knowledge gained from these studies to the electronic-state analysis of materials relevant to energy and environmental challenges, thereby contributing to the development of a sustainable society.
