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Seniorfellow Takeshi Morikawa Seniorfellow Takeshi Morikawa

Eclipsing plant photosynthesis

Senior Fellow

Takeshi Morikawa

Academic Degree ： Dr.Eng.
Research Fields ： Photocatalysis, Photofunctional Materials, Electrocatalysis, Enerygy Conversion

SENIOR FELLOW TAKESHI MORIKAWA SENIOR FELLOW TAKESHI MORIKAWA
Seniorfellow Hideo Iizuka Seniorfellow Hideo Iizuka

Proposing never-seen-before
devices based on the laws of physics

Senior Fellow

Hideo Iizuka

Academic Degree ： Dr.Eng.
Research Fields ： Wave Matter Interaction, Applied Physics

Research

Overview

We live side by side with many kinds of waves. Whenever we communicate with someone using a smart phone, we are using radio waves, visible light, sound waves, and even vibrational waves. All these waves follow the laws of physics. If we can manipulate these waves freely, then we can make our lives even more convenient. When looked at from all sides, physics shows us some extremely interesting possibilities. For example, in 1998, C. M. Bender et al. stated that eigenvalues of a system can be expressed as real numbers if the gain and loss of the system are combined. In 2021, we applied the idea behind this physical law to the field of power electronics and succeeded in suppressing unwanted oscillation that was causing a bottleneck in high-speed switching. Working together with the Toyota group of companies and other collaborators, we are trying to expand on concepts of quantum mechanics such as these to help realize significant devices with the capability of opening up an even brighter future.

長寿命・高出力リチウムイオン二次電池の概要図
Paper List
  • Yatsugi, K., Oishi, K. and Iizuka, H., “Ringing Suppression of SiC MOSFET Using a Strongly Coupled External Resonator through Analogy with Passive PT-symmetry”, IEEE Trans. Power Electronics, Vol. 36 (2021), pp. 2964-2970.
    https://doi.org/10.1109/TPEL.2020.3013399
  • Lee, T., Hashemi, D., Yatsugi, K., Yasunishi, M., Yoshimoto, H. and Iizuka, H., “Fano Resonance among Magnetic Coils for Midrange Position Sensing Capability”, IEEE Access, Vol.9 (2021), pp.15623-15632.
    https://doi.org/10.1109/ACCESS.2021.3052689
  • Lee, T., Noumura, T., Su, X. and H. Iizuka, “Fano-like Acoustic Resonance for Subwavelength Directional Sensing: 0-360 Degree Measurement”, Advanced Science, Vol.7 (2020), 1903101.
    https://doi.org/10.1002/advs.201903101
  • Iizuka, H. and Fan, S., “Significant Enhancement of Near-field Electromagnetic Heat Transfer in a Multilayer Structure through Multiple Surface-states Coupling”, Physical Review Letters, Vol. 120 (2018), 063901.
    https://doi.org/10.1103/PhysRevLett.120.063901
  • Ito, K., Nishikawa, K., Miura, A., Toshiyoshi, H. and Iizuka, H., “Dynamic Modulation of Radiative Heat Transfer beyond the Blackbody Limit”, Nano Letters, Vol. 17 (2017), pp.4347-4353.
    https://doi.org/10.1021/acs.nanolett.7b01422
Seniorfellow Ryosuke Jinnouchi Seniorfellow Ryosuke Jinnouchi

Realization of digital twins based on computational physics and electrode reaction site design

Seniorfellow

Ryosuke Jinnouchi

Academic Degree ： Dr.Eng.
Research Fields ： Computational Physics, Physical Chemistry

Research

Overview

In 1928, Paul Dirac discovered the equation governing fermions in condensed matter. However, in fuel cell research, it is not possible to design high-performance electrode materials based on this equation alone. Using this equation as a starting point, we are designing useful industrial materials, such as electrodes and electrolytes for enhancing the performance of fuel cells. We are also aiming to build computational techniques capable of predicting the performance of devices using these materials. Using first principle calculation and molecular modeling, we have identified the source of interface transport resistance at electrode reaction sites. In addition, to expand the scope of these computations, we have also developed machine learning technology capable of increasing the calculation speeds by 100 to 1,000 times while maintaining accuracy. We are continuing to enhance these computational techniques to enable an integrated approach to phenomena inside electrodes and electrolytes, with the aim of realizing a universal approach to designing the ideal fuel cell.

燃料電池電極への応用例
 Paper List
  • Jinnouchi, R., Karsai,F. and Kresse, G., “Making Free-energy Calculations Routine: Combining First Principles with Machine Learning”, Physical Review B, Vol. 101 (2020), 060201(R).
    https://doi.org/10.1103/PhysRevB.101.060201
  • Jinnouchi, R., Miwa, K., Karsai, F., Kresse, G. and Asahi, R., “On-the-fly Active Learning of Interatomic Potentials for Large-scale Atomistic Simulations”, Journal of Physical Chemistry Letters, Vol. 11 (2020), pp. 6946–6955.
    https://doi.org/10.1021/acs.jpclett.0c01061
  • Jinnouchi, R., Karsai, F. and Kresse, G., “On-the-fly Machine Learning Force Field Generation: Application to Melting Points”, Physical Review B, Vol. 100 (2019), 014105.
    https://journals.aps.org/prb/pdf/10.1103/PhysRevB.100.014105
  • Jinnouchi, R., Lahnsteiner, J., Karsai, F., Kresse, G. and Bokdam, M., “Phase Transitions of Hybrid Perovskites Simulated by Machine-learning Force Fields Trained on the Fly with Bayesian Inference”, Physical Review Letter, Vol. 122 (2019), 225701.
    https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.122.225701
  • Jinnouchi, R. and Asahi, R., “Predicting Catalytic Activity of Nanoparticles by a DFT-aided Machine-learning Algorithm”, Journal of Physical Chemistry Letters, Vol. 8 (2017), pp. 4279–4283.
    https://doi.org/10.1021/acs.jpclett.7b02010
Seniorfellow Daisuke Nakamura Seniorfellow Daisuke Nakamura

Next-generation semiconductors that will support the vehicles and cities of the future

Seniorfellow

Daisuke Nakamura

 Academic Degree：Dr.Eng.
Research Fields ：Crystal Growth, Surface Science, Ceramics

Research

Overview

Compounds such as silicon carbide (SiC) and gallium nitride (GaN) are regarded as promising next-generation semiconductors with the potential to help process vast amounts of information under severe operating environments like autonomous driving. Unlike today’s silicon semiconductors, which are grown as crystals from molten liquid, compounds like SiC and GaN must be crystallized using gaseous materials. At the beginning, this research primarily focused on the restoration of defects occurring during crystal growth. During this phase, it was found that defects could be efficiently pushed out by the next seed crystal parallel to the direction of growth, which resulted in the identification of a new law affecting SiC bulk crystal growth. In 2004, in a joint project with Denso, we succeeded in reducing the number of defects in a single SiC crystal by a factor of between two and three. We are currently researching ways of reducing the cost of high-quality SiC while studying new growth methods for defect-free GaN crystals. We are aiming to identify effective methods of fabricating next-generation semiconductors based on an overall standpoint of quality and manufacturing costs.

低コスト化を可能にする結晶成長部材の試作品

Coated materials for low-cost crystal growth
(φ320mm susceptor）and SiC wafers (φ2, 3, and 4 inch）

 Paper List
  • Nakamura, D., Kimura, T., Itoh, K., Fujimoto, N., Nitta, S. and Amano, H., “Tungsten Carbide Layers Deposited on Graphite Substrates via a Wet Powder Process as Anti-parasitic-reaction Coatings for Reactor Components in GaN Growth”, CrystEngComm, Vol. 22 (2020), pp. 2632-2641.
    https://doi.org/10.1039/C9CE01971E
  • Nakamura, D., Shigetoh, K. and Suzumura, A., “Tantalum Carbide Coating via Wet Powder Process: From Slurry Design to Practical Process Tests”, Journal of the European Ceramic Society, Vol. 37 (2017), pp. 1175-1185.
    https://doi.org/10.1016/j.jeurceramsoc.2016.10.029
  • Nakamura, D., Kimura, T. and Horibuchi, K., “Halogen-free Vapor Phase Epitaxy for High-rate Growth of GaN Bulk Crystals”, Applied Physics Express, Vol. 10 (2017), 045504.
    https://doi.org/10.7567/APEX.10.045504
  • Nakamura, D., Suzumura, A. and Shigetoh, K., “Sintered Tantalum Carbide Coatings on Graphite Substrates: Highly Reliable Protective Coatings for Bulk and Epitaxial Growth”, Applied Physics Letters, Vol. 106 (2015), 082108.
    https://doi.org/10.1063/1.4913413
  • Nakamura, D., Gunjishima, I., Yamaguchi, S., Ito, T., Okamoto, A., Kondo, H., Onda, S. and Takatori, K.,“Ultrahigh-quality Silicon Carbide Single Crystals”, Nature, Vol. 430 (2004), pp. 1009-1012.
    https://doi.org/10.1038/nature02810

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