Frontier Research Institute for Interdisciplinary Sciences
Tohoku University

Researchers from Tohoku University and the Massachusetts Institute of Technology (MIT) have unveiled a new AI tool for high-quality optical spectra with the same accuracy as quantum simulations, but working a million times faster, potentially accelerating the development of photovoltaic and quantum materials.   Understanding the optical properties of materials is essential for developing optoelectronic devices, such as LEDs, solar cells, photodetectors, and photonic integrated circuits. These devices are pivotal in the semiconductor industry's current resurgence.   Traditional means of calculation using the basic laws of physics involve complex mathematical calculations and immense computational power, rendering it difficult to quickly test a large number of materials. Overcoming this challenge could lead to the discovery of new photovoltaic materials for energy conversion and a deeper understanding of the fundamental physics of materials through their optical spectra.   A team led by Nguyen Tuan Hung, an assistant professor at the Frontier Institute for Interdisciplinary Science (FRIS), Tohoku University, and Mingda Li, an associate professor at MIT’s Department of Nuclear Science and Engineering (NSE), did just that, introducing a new AI model that predicts optical properties across a wide range of light frequency, using only a material’s crystal structure as an input. Lead author Nguyen and his colleagues recently published their findings in an open-access paper in “Advanced Materials.”   “Optics is a fascinating aspect of condensed matter physics, governed by the causal relationship known as the Kramers-Krönig (KK) relation”, says Nguyen. “Once one optical property is known, all other optical properties can be derived using the KK relation. It is intriguing to observe how AI models can grasp physics concepts through this relation.”   Obtaining optical spectra with complete frequency coverage in experiments is challenging due to the limitations of laser wavelengths. Simulations are also complex, requiring high convergence criteria and incurring significant computational costs. As a result, the scientific community has long been searching for more efficient methods to predict the optical spectra of various materials.   “Machine-learning models utilized for optical prediction are called graph neural networks (GNNs),” points out Ryotaro Okabe, a chemistry graduate student at MIT. “GNNs provide a natural representation of molecules and materials by representing atoms as graph nodes and interatomic bonds as graph edges.”   Yet, while GNNs have shown promise for predicting material properties, they lack universality, especially in representations of crystal structures. To work around this conundrum, Nguyen and others devised a universal ensemble embedding, whereby multiple models or algorithms are created to unify the data representation.   "This ensemble embedding goes beyond human intuition but is broadly applicable to improve prediction accuracy without affecting neural network structures," explains Abhijatmedhi Chotrattanapituk, an electrical engineering and computer science graduate student at MIT.   The ensemble embedding method is a universal layer that can be seamlessly applied to any neural network model without modifying the neural network structures. “This implies that universal embedding can readily be integrated into any machine learning architecture, potentially making a profound impact on data science,” says Mingda Li.   This method enables highly precise optical prediction based solely on crystal structures, making it suitable for a wide variety of applications, such as screening materials for high-performance solar cells and detecting quantum materials.   Looking ahead, the researchers aim to develop new databases for various material properties, such as mechanical and magnetic characteristics, to enhance the AI model’s capability to predict material properties based solely on crystal structures.   Figure: An AI tool called GNNOpt can accurately predict optical spectra based solely on crystal structures and speed up the development of photovoltaic and quantum materials. Publication Details: •Title: Universal Ensemble-Embedding Graph Neural Network for Direct Prediction of Optical Spectra from Crystal Structures •Author: Nguyen Tuan Hung, Ryotaro Okabe, Abhijatmedhi Chotrattanapituk, Mingda Li •Journal: Advanced Materials •DOI: 10.1002/adma.202409175 •URL: https://onlinelibrary.wiley.com/doi/10.1002/adma.202409175 Press Release: Tohoku University https://www.tohoku.ac.jp/en/press/ai_speeds_up_discovery_of_energy_and_quantum_materials.html  

Quantum squeezing is a concept in quantum physics where the uncertainty in one aspect of a system is reduced while the uncertainty in another related aspect is increased. Imagine squeezing a round balloon filled with air. In its normal state, the balloon is perfectly spherical. When you squeeze one side, it gets flattened and stretched out in the other direction. This represents what is happening in a squeezed quantum state: you are reducing the uncertainty (or noise) in one quantity, like position, but in doing so, you increase the uncertainty in another quantity, like momentum. However, the total uncertainty remains the same, since you are just redistributing it between the two. Even though the overall uncertainty remains the same, this ‘squeezing’ allows you to measure one of those variables with much greater precision than before.   This technique has already been used to improve the accuracy of measurements in situations where only one variable needs to be precisely measured, such as in improving the precision of atomic clocks. However, using squeezing in cases where multiple factors need to be measured simultaneously, such as an object's position and momentum, is much more challenging.   In a research paper published in Physical Review Research, Tohoku University’s Dr. Le Bin Ho explores the effectiveness of the squeezing technique in enhancing the precision of measurements in quantum systems with multiple factors. The analysis provides theoretical and numerical insights, aiding in the identification of mechanisms for achieving maximum precision in these intricate measurements. "The research aims to better understand how quantum squeezing can be used in more complicated measurement situations involving the estimation of multiple phases," said Le. "By figuring out how to achieve the highest level of precision, we can pave the way for new technological breakthroughs in quantum sensing and imaging."   The study looked at a situation where a three-dimensional magnetic field interacts with an ensemble of identical two-level quantum systems. In ideal cases, the precision of the measurements can be as accurate as theoretically possible. However, earlier research has struggled to explain how this works, especially in real-world situations where only one direction achieves full quantum entanglement. This research will have broad implications. By making quantum measurements more precise for multiple phases, it could significantly advance various technologies. For example, quantum imaging could produce sharper images, quantum radar could detect objects more accurately, and atomic clocks could become even more precise, improving GPS and other time-sensitive technologies. In biophysics, it could lead to advancements in techniques like MRI and enhance the accuracy of molecular and cellular measurements, improving the sensitivity of biosensors used in detecting diseases early. "Our findings contribute to a deeper understanding of the mechanisms behind the improvement of measurement precision in quantum sensing," adds Le. "This research not only pushes the boundaries of quantum science, but also lays the groundwork for the next generation of quantum technologies." Looking ahead, Le hopes to explore how this mechanism changes with different types of noise and explore ways to reduce it.     Figure: A visual comparison between the familiar act of squeezing a lemon and the concept of quantum squeezing in a sensor. (License: CC BY-NC-SA) Publication Details: •Title: Squeezing-induced quantum-enhanced multiphase estimation •Author: Le Bin Ho •Journal: Physical Review Research •DOI: 10.1103/PhysRevResearch.6.033292 •URL: https://journals.aps.org/prresearch/pdf/10.1103/PhysRevResearch.6.033292   Press Release: Tohoku University https://www.tohoku.ac.jp/en/press/squeezing_increased_accuracy_out_of_quantum_measurements.html  

Researchers at Tohoku University and Utsunomiya University have made a breakthrough in understanding the complex nature of turbulence in structures called “accretion disks” surrounding black holes, using state-of-the-art supercomputers to conduct the highest-resolution simulations to date. An accretion disk, as the name implies, is a disk-shaped gas that spirals inwards towards a central black hole.   There is a great interest in studying the unique and extreme properties of black holes. However, black holes do not allow light to escape, and therefore cannot be directly perceived by telescopes. In order to probe black holes and study them, we look at how they affect their surroundings instead. Accretion disks are one such way to indirectly observe the effects of black holes, as they emit electromagnetic radiation that can be seen by telescopes.   “Accurately simulating the behaviour of accretion disks significantly advances our understanding of physical phenomena around black holes,” explains Yohei Kawazura, “It provides crucial insights for interpreting observational data from the Event Horizon Telescope.”   The researchers utilized supercomputers such as RIKEN's "Fugaku" (the fastest computer in the world up until 2022) and NAOJ's "ATERUI II" to perform unprecedentedly high-resolution simulations. Although there have been previous numerical simulations of accretion disks, none have observed the inertial range because of the lack of computational resources. This study was the first to successfully reproduce the "inertial range" connecting large and small eddies in accretion disk turbulence.   It was also discovered that "slow magnetosonic waves" dominate this range. This finding explains why ions are selectively heated in accretion disks. The turbulent electromagnetic fields in accretion disks interact with charged particles, potentially accelerating some to extremely high energies. Figure: Artistic image of accretion disk turbulence. The inset is the magnetic field fluctuations computed by the simulation of this study. ©Yohei Kawazura In magnetohydronamics, magnetosonic waves (slow and fast) and Alfvén waves make up the basic types of waves. Slow magnetosonic waves were found to dominate the inertial range, carrying about twice the energy of Alfvén waves. The research also highlights a fundamental difference between accretion disk turbulence and solar wind turbulence, where Alfvén waves dominate.   This advancement is expected to improve the physical interpretation of observational data from radio telescopes focused on regions near black holes. The study was published in Science Advances on August 28, 2024. Publication Details: Title: Inertial range of magnetorotational turbulence Authors: Yohei Kawazura and Shigeo S. Kimura Journal: Science Advances DOI: 10.1126/sciadv.adp4965 URL: https://www.science.org/doi/10.1126/sciadv.adp4965 Press Release: Tohoku University https://www.tohoku.ac.jp/en/press/supercomputer_simulations_reveal_the_nature_of_turbulence_in_black_hole_accretion_disks.html

Spin-glass states, a fascinating phenomenon in magnetic materials, have been successfully generated in a van der Waals (vdW) magnet through alkali-ion intercalation. This groundbreaking study, published in Advanced Materials on July 22, 2024, opens new avenues in magnetic materials research and potential applications in advanced technologies.   Researchers from University College London, led by Dr. Safe Khan, and international collaborators, including Dr. Aakanksha Sud from FRIS, discovered this novel way to manipulate the magnetic properties of vdW materials. By intercalating sodium (Na) atoms into the vdW material Cr2Ge2Te6 (CGT), they enhanced the Curie temperature (TC) from 66 K to 240 K and altered the magnetic easy-hard axis direction. This process created a system where magnetic frustration leads to the coexistence of spin-glass states and ferromagnetic order, showcasing a new method for tuning magnetic properties in 2D materials.   Dynamic magnetic susceptibility measurements confirmed the formation of magnetic clusters with slow dynamics and a distribution of relaxation times, opening new possibilities for understanding complex magnetic behaviours and enhancing magnetic material performance.   The authors commented, "Our research highlights the potential of intercalation as a unique method to induce magnetic frustration and generate spin-glass states in simple vdW crystals. This could lead to new functionalities in magnetic materials and advanced technological applications."   This research provides valuable insights into the fundamental properties of spin-glass states in vdW materials, with potential implications for advanced magnetic applications and theoretical models. This discovery was published in Advanced Materials on July 22, 2024.     Figure: (a) The image represents the process of sodium (Na) atom intercalation into the vdW gaps of pristine Cr2Ge2Te6 (CGT), generating spin-glass states that coexist with ferromagnetic order, enhancing the Curie temperature (TC) and altering the magnetic axis direction   (b) Shift in peak position of magnetic susceptibility (χ') for a frequency window of Hz–kHz indicating slow dynamics in the system and emerging spin-glass state. Publication Details Title: Spin-Glass States Generated in a van der Waals Magnet by Alkali-Ion Intercalation Authors: Safe Khan, Eva S. Y. Aw, Liam A. V. Nagle-Cocco, Aakanksha Sud, Sukanya Ghosh, Mohammed K. B. Subhan, Zekun Xue, Charlie Freeman, Dimitrios Sagkovits, Araceli Gutiérrez-Llorente, Ivan Verzhbitskiy, Daan M. Arroo, Christoph W. Zollitsch, Goki Eda, Elton J. G. Santos, Sian E. Dutton, Steven T. Bramwell, Chris A. Howard, Hidekazu Kurebayashi Journal: Advanced Materials DOI: 10.1002/adma.202400270 URL: https://doi.org/10.1002/adma.202400270

Terahertz waves are being intensely studied by researchers around the world seeking to understand the "terahertz gap". Terahertz waves have a specific frequency that puts them somewhere between microwaves and infrared light. This range is referred to as a "gap" because much remains unknown about these waves. In fact, it was only relatively recently that researchers were able to develop the technology to generate them. Researchers at Tohoku University have brought us closer to understanding these waves and filling in this gap of knowledge.   Researchers at the Advanced Institute for Materials Research (WPI-AIMR), Graduate School of Engineering, and Frontier Research Institute for Interdisciplinary Sciences (FRIS) have discovered a new magnetic material that generates terahertz waves at an intensity about four times higher than that of typical magnetic materials.   Taking advantage of the features unique to terahertz waves, this technology is expected to be used in a variety of industrial fields, including imaging, medical diagnostics, security inspection, and biotechnology. Assistant Professor Ruma Mandal (WPI-AIMR) explains, "Terahertz waves have low photon energies and unlike X-rays, they don't emit ionizing radiation. So, if they are used for patient imaging or microscopes, they may be less damaging to tissues or samples." This work was published in NPG Asia Materials on June 7, 2024.     Figure: Weyl magnet: schematic diagram of a crystal of cobalt-manganese-gallium Heusler alloy (Co2MnGa). (b) Light-induced terahertz waves. ©Shigemi Mizukami Publication Details: Title: Topologically influenced terahertz emission in Co2MnGa with large anomalous Hall effect Authors: Ruma Mandal, Ren Momma, Kazuaki Ishibashi, Satoshi Iihama, Kazuya Suzuki, and Shigemi Mizukami Journal: NPG Asia Materials DOI: https://doi.org/10.1038/s41427-024-00545-9 Press Release: Tohoku University https://www.tohoku.ac.jp/en/press/making_waves_generation_of_intense_terahertz_waves_with_a_magnetic_material.html   The Advanced Institute for Materials Research (AIMR), Tohoku University https://www.wpi-aimr.tohoku.ac.jp/en/achievements/press/2024/20240610_001808.html   School of Engineering, Tohoku University https://www.eng.tohoku.ac.jp/english/news/detail-,-id,2913.html

The application requirement states that when asking a faculty member to be a mentor, the applicant and the mentor candidate must agree with the "Internal regulations on the mentors of the Frontier Research Institute for Interdisciplinary Sciences". In addition, applicants and their mentor candidates must consult the “checklist for the Internal regulations on the mentors of the Frontier Research Institute for Interdisciplinary Sciences". Download the checklist here   The information session (June 17, 2024) has ended. The recording of the session (excluding the Q&A part) and the questions and answers are now available. Recording of the information session Questions and answers   Number of Positions   Seven Assistant Professor Positions (Following the FRIS fundamental policy of promoting Diversity, Equity & Inclusion, we welcome applications from all backgrounds.) Organization and Department Creative Interdisciplinary Research Division, Frontier Research Institute for Interdisciplinary Sciences (FRIS), Tohoku University, Sendai, Japan Research Areas and Job Description We recruit people in six research areas (1. Materials and Energy, 2. Life and Environments, 3. Information and Systems, 4. Device and Technology, 5. Human and Society, 6. Advanced Basic Science). Successful applicants are expected to promote international interdisciplinary scientific research on their own initiative as Principal Investigators (PIs) and have a strong will to develop new academic disciplines. To achieve these, they are expected to collaborate actively with researchers and research institutions at home and abroad. This recruitment is part of the “Frontier Researchers for Interdisciplinary Sciences Shoshi Program (FRIS Shoshi Program),” a university-wide initiative to support young researchers under the Tohoku University Comprehensive Package for Supporting Young Researchers. For more information about the “FRIS Shoshi Program,” please visit the following URL. https://www.fris.tohoku.ac.jp/en/about/missions/fostering.html Research Funding The following research funding will be provided. Basic research funding of 11 million yen over five years (2.5 million yen per year for the first three years, 2 million yen for the fourth year, and 1.5 million yen for the fifth year, but it allows flexible budget execution by carry-over.)   Upon review, we provide expenses for overseas travel to present research results at international conferences and conduct collaborative research, for collaborative research with researchers in different fields, for organizing international conferences, and so forth. In addition to the above, successful applicants are expected to actively seek external competitive funds such as Grant-in-Aid for Scientific Research (KAKENHI). Eligibility PhD degree by the time of appointment Starting Date April 1, 2025 (subject to negotiation) Term of Appointment Five years (no reappointment) Under the tenure track system at FRIS, assistant professors undergo a predetermined review process. Successful completion of this process leads to their appointment as either tenured assistant professors or fixed-term (five-year) associate professors by the end of their appointment term. If they do not pass the review, their term can be extended by one year (maximum two years) after a separate review. Furthermore, although this is not guaranteed, they may remain employed as faculty members in other departments or institutes. For more details, please visit the following URL. # Tenure track system at FRIS: https://www.fris.tohoku.ac.jp/en/about/tenure-track.html   In the case of taking childcare leave, the term of employment may be extended by up to the number of days taken off for the leave if deemed necessary for educational and research purposes. Remuneration Annual salary system. Other allowances will be provided according to the regulations of Tohoku University. Notes on Application Applicants must select one area of research they wish to apply from the six research areas indicated above. Please note that the review committee may change the research area of their selection. When applying, applicants must provide information about their mentors. A mentor must be a full-time professor or associate professor at Tohoku University (visiting or specially appointed professors are not eligible). Prior to applying, applicants must obtain their mentors’ consent regarding the internal regulations on the mentor system and the attached description of their responsibilities shown at the URL below. We prioritize that the mentors can allow FRIS assistant professors to have experiences in various research environments, such as selecting a mentor from outside their previously-affiliated laboratory. Successful applicants must be independent as a PI during the term of their appointment. For the selection of mentors, the following websites can be helpful. Please visit the URLs below. # Internal regulations on the mentors and the responsibilities of mentors https://www.fris.tohoku.ac.jp/media/files/mentorregulations_rev20220620_EN.pdf (English) https://www.fris.tohoku.ac.jp/media/files/mentorregulations_rev20220620_JP.pdf (Japanese) # Tohoku University Researchers: https://www.r-info.tohoku.ac.jp/ Application Deadline Applications must be submitted by 17:00, Friday, July 26, 2024 (JST) Required Documents Following the instructions in the section “How to Apply”, applicants must complete the application online and electronically submit the documents indicated below. All documents must be prepared in PDF format, and the total file size must not exceed 10 MB. For (3) Research Proposal, please download the template from our website, as shown below. https://www.fris.tohoku.ac.jp/en/recruit/invitation/   (1) A list of research achievements such as publications: original research papers, international conference proceedings, books and editorials/commentaries, conference presentations (indicating domestic or international, and with or without invitation), awards, patents, competitive research funds, achievements of collaborative research, and other notable mentions.   (2) A brief overview of your research achievements (less than 400 words) (3) A research proposal (in our provided format, within four pages) (4) A letter of recommendation (in any format) (5) A summary of up to five significant papers or major achievements, each demonstrating excellence in its field. (If any, please show any numerical indicators that highli How to Apply Please apply from the application website below. Once applicants complete the pre-registration, they will receive a URL to complete the registration. They must upload the required documents to “My Page.” After completing the upload, they will receive a confirmation email.   # Application website https://rct4osp.fris.tohoku.ac.jp/en # You can also visit the application website from the recruitment information page in the FRIS website below. https://www.fris.tohoku.ac.jp/en/ Inquiries Professor Junji Saida, Managing and Planning Division, FRIS E-mail: kikaku-hr_atmk_fris.tohoku.ac.jp (Please replace “_atmk_” with “@”) DEI Promotion Aiming to be a leading research institute in Diversity, Equity and Inclusion (DEI), FRIS has enacted a fundamental policy of promoting DEI and established a working group to implement this policy. We are committed to creating an environment that facilitates research, education and employment for all members of the institute, and supporting the implementation of this goal.   Tohoku University promotes activities to increase DEI and encourages people of varied talents from all backgrounds to apply for positions at the university. Tohoku University's website about the DEI Declaration is here: https://dei.tohoku.ac.jp/vision/about/   Under Article 8 of the Act on Securing, Etc. of Equal Opportunity and Treatment between Men and Women in Employment, Tohoku University shall, as a measure for increasing the presence of women among the academic staff, prioritize the hiring of women deemed qualified for each job opening, based on impartial evaluation.   Tohoku University has published 'Tohoku University ‐ Live as Who You Are ‐ Guidelines for Gender and Sexual Diversity' to provide explanations and details of how those at the university should respond concerning diverse sexuality. The guidelines aim to create an environment in which all students, faculty, and staff respect diverse sexuality in their academic, research, and professional activities. Please see the Center for Diversity, Equity, and Inclusion, Tohoku University website: https://dei.tohoku.ac.jp/vision/consulting/for_minority/   Tohoku University has the most extensive on-campus childcare system of all Japanese national universities. This network comprises three nurseries: Kawauchi Keyaki Nursery School (capacity: 22) as well as Aobayama Midori Nursery School (116), both open to all university employees and Hoshinoko Nursery School (120), which is open to employees working on Tohoku University Hospital. In addition, Tohoku University Hospital runs a childcare room for mildly ill and convalescent children which is available to all university employees.   See the following website for information on these and other programs that Tohoku University runs to assist work-life balance, support researchers, and advance gender equality, including measures to promote childcare leave among male employees.   Center for Diversity, Equity, and Inclusion, Tohoku University website: https://dei.tohoku.ac.jp/vision/consulting/for_family/ Human Resources and Planning Department website: https://c.bureau.tohoku.ac.jp/jinji-top/external/a-4-kosodate/ Other An information session for this recruitment will be held on June 17 (Monday), 2024, between 15:00 and 16:00. If one wishes to attend the session, please complete the registration on the webpage below. Registration for information session: https://us02web.zoom.us/meeting/register/tZcldumrqjIuGNPnJnOHeqJ1fZu437ZWgLSJ   After the first screening, as a general rule of the FRIS recruitment process, successful candidates will be asked for an online interview on September 30 (Monday), October 1 (Tuesday) or October 2 (Wednesday), 2024. They will be provided with detailed information in early September 2024.   FRIS is developing FRIS CoRE (Cooperative Research Environment), a new form of “start-up support” proposed by young researchers at FRIS, that aims to promote interdisciplinary fusion and explore the frontiers of knowledge. It provides under-one-roof access to basic research facilities in different fields –a research environment for daily experiments and discussions. The current experimental facilities are used for life science, chemistry, and engineering, but in the future, FRIS CoRE will expand its collaborative environment for researchers in the humanities and social sciences. FRIS CoRE will also provide facilities in fields other than the mentor's expertise. Please visit the following website to learn the status of FRIS CoRE. # FRIS CoRE: https://www.fris.tohoku.ac.jp/fris_core/en/

A group of researchers have expanded conventional knowledge on a critical enzyme that controls cell migration. In a recent publication in the journal Nature Communications, they reported that phosphoinositide 3-kinase (PI3K) not only acts as an accelerator to prompt cell motility, but it also has a built-in brake mechanism that impedes migration. Figure: Traditionally viewed as a catalyst for cell migration, PI3K reveals a hidden regulatory mechanism. Here, authors uncover the PI3K's interaction with AP2 induces endocytosis, braking cell migration independently of its catalytic function. “PI3K is a major signaling enzyme that has been extensively studied for over 30 years due to its roles in fundamental cellular functions like growth, survival, movement and metabolism,” points out Hideaki Matsubayashi, lead author of the study and assistant professor at Tohoku University's Frontier Research Institute for Interdisciplinary Sciences (FRIS). “It plays a critical part in cell migration and invasion, something that when dysregulated, can cause many pathologies. Our work revealed that PI3K can also actively restrain these same migratory processes through a separate non-catalytic endocytic mechanism originating from its p85β subunit.”   Using a combination of bioinformatics, molecular modeling, biochemical binding assays and live-cell imaging, Matsubayashi and his colleagues demonstrated that a disordered region within p85β's inter-SH2 domain directly binds to the endocytic protein AP2. This part of PI3K can activate a cellular process that pulls certain molecules into the cell, and it does so without needing the enzyme's typical lipid-modification function .   When the researchers disrupted the binding  , the mutated p85β did not function as it should. Instead of regulating cell movement through its brake mechanism, it built up in specific sites within the cell. This leads to cells moving faster and more persistently, indicating a loss of the brake mechanism's control over cell migration.   “Remarkably, this single PI3K enzyme has opposing accelerator and brake pedals built into its molecular framework," added Matsubayashi. “The endocytic mechanism helps regulate PI3K's activity to ensure that cell movement is controlled at the right times and in the right places for important biological processes.”   This braking role was found to be specific to just the p85β subunit. And since the p85β subunit of PI3K is linked to cancer-promoting properties, deeper understanding of PI3K regulation and its isoform specificity could lead to novel therapeutic strategies, such that selectively inhibit the cancerous aspect of PI3K, while preserving the normal functions of PI3K in healthy cells. Publication Details: Title: Non-catalytic role of phosphoinositide 3-kinase in mesenchymal cell migration through non-canonical induction of p85β/AP2-mediated endocytosis Authors: Hideaki T. Matsubayashi, Jack Mountain, Nozomi Takahashi, Abhijit Deb Roy, Tony Yao, AmyF.Peterson, Cristian Saez Gonzalez, Ibuki Kawamata & Takanari Inoue Journal: Nature Communications DOI: https://doi.org/10.1038/s41467-024-46855-y   Press Release: Tohoku University https://www.tohoku.ac.jp/en/press/researchers_unveil_pi3k_enzymes_dual_accelerator_and_brake_mechanisms.html  

Researchers at Tohoku University including Assistant Professor Kohei Shimokawa at Frontier Research Institute for Interdisciplinary Sciences (FRIS) have made a groundbreaking advancement in battery technology, developing a novel cathode material for rechargeable magnesium batteries (RMBs) that enables efficient charging and discharging even at low temperatures. This innovative material, leveraging an enhanced rock-salt structure, promises to usher in a new era of energy storage solutions that are more affordable, safer, and higher in capacity.   Details of the findings were published in the Journal of Materials Chemistry A on March 15, 2024.   Figure: Schematics of the battery and present cathode material. The present material contains many metal elements as cations thanks to the effect of the high configurational entropy. (Credit: Tohoku University) The study showcases a considerable improvement in magnesium (Mg) diffusion within a rock-salt structure, a critical advancement since the denseness of atoms in this configuration had previously impeded Mg migration. By introducing a strategic mixture of seven different metallic elements, the research team created a crystal structure abundant in stable cation vacancies, facilitating easier Mg insertion and extraction.   This represents the first utilization of rocksalt oxide as a cathode material for RMBs. The high-entropy strategy employed by the researchers allowed the cation defects to activate the rocksalt oxide cathode.   The development also addresses a key limitation of RMBs - the difficulty of Mg transport within solid materials. Until now, high temperatures were necessary to enhance Mg mobility in conventional cathode materials, such as those with a spinel structure. However, the material unveiled by Tohoku University researchers operates efficiently at just 90°C, demonstrating a significant reduction in the required operating temperature.   Tomoya Kawaguchi, a professor at Tohoku University's Institute for Materials Research (IMR), notes the broader implications of the study. "Lithium is scarce and unevenly distributed, whereas magnesium is abundantly available, offering a more sustainable and cost-effective alternative for lithium-ion batteries. Magnesium batteries, featuring the newly developed cathode material, are poised to play a pivotal role in various applications, including grid storage, electric vehicles, and portable electronic devices, contributing to the global shift towards renewable energy and reduced carbon footprints."   Kawaguchi collaborated with Tetsu Ichitsubo, also a professor at IMR, who states, "By harnessing the intrinsic benefits of magnesium and overcoming previous material limitations, this research paves the way for the next generation of batteries, promising significant impacts on technology, the environment, and society."   Ultimately, the breakthrough is a major step forward in the quest for efficient, eco-friendly energy storage solutions. Publication Details: Title: Securing cation vacancies to enable reversible Mg insertion/extraction in rocksalt oxides Authors: Tomoya Kawaguchi, Masaya Yasuda, Natsumi Nemoto, Kohei Shimokawa, Hongyi Li, Norihiko L. Okamoto, and Tetsu Ichitsubo Journal: Journal of Materials Chemistry A DOI: https://pubs.rsc.org/doi/D3TA07942B Press Release: Tohoku University https://www.tohoku.ac.jp/en/press/unleashing_disordered_rocksalt_oxides_as_cathodes_for_rechargeable_magnesium_batteries.html Institute for Materials Research, Tohoku University https://www.imr.tohoku.ac.jp/en/news/results/detail---id-1593.html  

Tohoku University's Frontier Research Institute for Interdisciplinary Sciences (FRIS) was established in 2013 through the merger of the International Advanced Center for Interdisciplinary Research, which was established in 1995 to promote interdisciplinary research, and the Advanced Fusion Research Laboratory, which has a new mission to foster young researchers. Since then, the Institute has been active with the missions of promoting advanced interdisciplinary research, fostering early-career researchers through the "FRIS Shoshi Program," and discovering interdisciplinary research within the University, and is now celebrating its 10th anniversary. To commemorate this anniversary, the 10th Anniversary Ceremony and Lectures of FRIS were held on Monday, February 19, 2024, at Katahira Sakura Hall, Tohoku University. The event was attended by approximately 120 people, including those who have supported the Institute in various ways, as well as current and former faculty members.   At the beginning of the ceremony, Tohoku University President Hideo Ohno opened the event with remarks on the role of FRIS at Tohoku University. He expressed his gratitude for the generous support from all quarters and stated, "The Institute has nurtured many researchers and serves as the foundation of our efforts to promote early-career researchers at Tohoku University. After a congratulatory address by Mr. Yasuyoshi Kakita, Director General of the Science and Technology Policy Bureau of the Ministry of Education, Culture, Sports, Science and Technology, Prof. Toshiyuki Hayase, Director of FRIS, gave an overview of the history and prospects of the Institute.   In the commemorative lecture, Dr. Hiroto Yasuura, Deputy Director General of the National Institute of Informatics, gave a presentation titled "Support for Early-Career Researchers and Transformation of Academic Information Infrastructure," in which he introduced Japan's efforts to foster early-career researchers. He concluded his lecture with the expectation that Tohoku University and FRIS will continue to be cutting-edge organizations in academia, even with new trends in data-driven research and open science.   In addition, Prof. Hiroshi Masumoto and Prof. Kenji Toma of FRIS gave talks on "Advanced Interdisciplinary Research at FRIS and the Future of Nanocomplex Materials" and "Interdisciplinary Exchange, Astrophysics Research, and their Future" respectively, and Assoc. Prof. Yui Arimatsu of Hiroshima University, a former FRIS faculty member, gave a talk on "Humanities at FRIS: What I Think as a FRIS's Alumnus and the Future of Western Asian Archaeology". They talked about the unique activities, roles, and various memories of FRIS from the viewpoints of both current and former Institute members.   It was noteworthy that about 30 researchers, who had previously been part of FRIS and are now active both inside and outside of the University, gathered at the event. The fact that these former members are now active in their respective fields truly testifies to the role and impact that FRIS has had in the past. Following the commemorative lecture, a poster session was held, featuring more than 60 presentations by both current and former members of FRIS. Afterward, a lively social gathering was held, during which attendees reflected on the history of the Institute and discussed their hopes for the future, celebrating the 10th anniversary of the establishment of FRIS. Photo: The ceremony celebrating the 10th anniversary of the establishment of FRIS.

A group of Tohoku University researchers including Assistant Professor Satoshi Iihama at Frontier Research Institute for Interdisciplinary Sciences (FRIS) has developed a theoretical model for a high-performance spin wave reservoir computing (RC) that utilizes spintronics technology. The breakthrough moves scientists closer to realizing energy-efficient, nanoscale computing with unparalleled computational power.   Details of their findings were published in npj Spintronics on March 1, 2024.     The brain is the ultimate computer and scientists are constantly striving to create neuromorphic devices that mimic the brain's processing capabilities, low power consumption, and its ability to adapt to neural networks. The development of neuromorphic computing is revolutionary, allowing scientists to explore nanoscale realms, GHz speed, with low energy consumption.   In recent years, many advances in computational models inspired by the brain have been made. These artificial neural networks have demonstrated extraordinary performances in various tasks. However, current technologies are software-based; their computational speed, size, and energy consumption remain constrained by the properties of conventional electric computers.   RC works via a fixed, randomly generated network called the ‘reservoir.’ The reservoir enables the memorization of past input information and its nonlinear transformation. This unique characteristic allows for the integration of physical systems, such as magnetization dynamics, to perform various tasks for sequential data, like time-series forecasting and speech recognition.   Some have proposed spintronics as a means to realize high-performance devices. But devices produced so far have failed to live up to expectations. In particular, they have failed to achieve high performance at nanoscales with GHz speed.   “Our study proposed a physical RC that harnessed propagating spin waves,” says Natsuhiko Yoshinaga, co-author of the paper and associate professor at the Advanced Institute for Materials Research (WPI-AIMR). “The theoretical framework we developed utilized response functions that link input signals to propagating spin dynamics. This theoretical model elucidated the mechanism behind the high performance of spin wave RC, highlighting the scaling relationship between wave speed and system size to optimize the effectiveness of virtual nodes.”   Crucially, Yoshinaga and his colleagues helped clarify the mechanism for high-performance reservoir computing. In doing so, they harnessed various subfields, namely condensed matter physics and mathematical modeling. “By employing the unique properties of spintronics technology, we have potentially paved the way for a new era of intelligent computing, leading us closer to realizing a physical device that can be put to use in weather forecasts and speech recognition" adds Yoshinaga. Figure: A physical reservoir computer performs a task to transform input data to output data, such as time-series prediction. We use magnetic thin film for the reservoir part. Information of the input is carried by spin waves and propagated to the output node (shown in blue cylinders in the bottom figure) corresponding to the nodes in the reservoir (shown in yellow in the top figure). (Credit: Springer Nature Limited) Publication Details: Title: Universal scaling between wave speed and size enables nanoscale high-performance reservoir computing based on propagating spin-waves Authors: S. Iihama, Y. Koike, S. Mizukami, and N. Yoshinaga Journal: npj Spintronics DOI：10.1038/s44306-024-00008-5 URL: https://doi.org/10.1038/s44306-024-00008-5 Press Release: Tohoku University https://www.tohoku.ac.jp/en/press/giant_leap_towards_neuromorphic_devices.html Advanced Institute for Materials Research (WPI-AIMR) https://www.wpi-aimr.tohoku.ac.jp/en/achievements/press/2024/20240304_001762.html