JSAP Review
Online ISSN : 2437-0061
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Displaying 1-7 of 7 articles from this issue
Tutorial Review
  • Takahiro Ito
    Article type: Tutorial Review
    2025 Volume 2025 Article ID: 250201
    Published: 2025
    Released on J-STAGE: January 09, 2025
    JOURNAL OPEN ACCESS

    Layered MAX phases (M: transition metal, A: III-A, IV-A group elements, X: C or N) are the parent materials of MXenes, which have recently received attention as a new atomic layer system and are known as industrial materials for applications owing to their excellent properties, which combine the characteristics of both metals and ceramics. Meanwhile, the bulk electronic structure of MAX phases has primarily been investigated using computational methods, primarily because well-characterized single crystals are few. This review presents anomalous electronic states such as Dirac points and line nodes, which have been observed in recent electronic structure studies pertaining to MAX phase single-crystals using angle-resolved photoemission spectroscopy. These states are expected to result in unique topological quantum transport in MAX phases.

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  • Toshiyuki Koyama
    Article type: Tutorial Review
    2025 Volume 2025 Article ID: 250202
    Published: 2025
    Released on J-STAGE: February 15, 2025
    JOURNAL OPEN ACCESS

    The phase-field method is a continuum model used to calculate internal microstructure developments in various materials. Over the past four decades, it has become one of the primary approaches for analyzing microstructures in materials. During this time, both computational thermodynamics (e.g., the CALPHAD method) and material property calculations based on microstructure data have also advanced significantly. Together, these methods are evolving into a robust system that supports multiple aspects of material design. Additionally, data-driven engineering methods can be broadly viewed as a collection of tools for handling forward and inverse models in computational engineering. This tutorial review explores perspectives on the next generation of material design by integrating these approaches.

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Research Report
  • Shunsuke Kamimura, Yuichiro Matsuzaki, Kyo Yoshida, Yasuhiro Tokura
    Article type: Research Report
    2025 Volume 2025 Article ID: 250401
    Published: 2025
    Released on J-STAGE: January 09, 2025
    JOURNAL OPEN ACCESS

    A device that converts thermal energy into extractable forms, such as mechanical energy, is termed as a heat engine. The operating medium that powers the heat engine is usually a physical system that follows classical physics. In recent years, research on heat engines, whose operating media follow quantum physics, has been progressing from theoretical and experimental perspectives. In this study, we focus primarily on the theoretical aspects, particularly on how the performance of this type of quantum heat engine improves with an increase in the size of the operating medium. We discuss the research background, recent trends in this field, and our latest findings. The results presented here suggest a significant potential for enhancing heat engine performance by leveraging quantum mechanics as the operating principle.

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  • Masaya Fujioka
    Article type: Research Report
    2025 Volume 2025 Article ID: 250402
    Published: 2025
    Released on J-STAGE: January 25, 2025
    JOURNAL OPEN ACCESS

    Materials informatics has significantly advanced the prediction technology for new materials. However, not all predicted materials can be synthesized. We have been developing synthesis techniques to handle metastable states and achieve more new materials. This article presents the methods to change the chemical composition while preserving crystal structures by controlling the diffusion of specific constituent elements.

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  • Masatoshi Sakai
    Article type: Research Report
    2025 Volume 2025 Article ID: 250403
    Published: 2025
    Released on J-STAGE: January 31, 2025
    JOURNAL OPEN ACCESS

    Time-domain reflectometry is an electrical measurement that utilizes the reflected waves of high-frequency electrical signals from portions where impedances are not matched in the high-frequency transmission paths. In the past, it has been used for large-scale measurements such as geological surveys. However, in recent years, technological advances have made it possible to perform small-scale measurements such as LSI quality diagnosis. We adopted this measurement to observe the carrier dynamics in electronic devices by measuring the transient impedance. This paper presents the results of a time-resolved analysis of organic thin-film transistors and organic solar cells.

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  • Masaharu Kobayashi
    Article type: Research Report
    2025 Volume 2025 Article ID: 250404
    Published: 2025
    Released on J-STAGE: February 06, 2025
    JOURNAL OPEN ACCESS

    As AI technology evolves and the demand for high-performance computing increases, high-capacity, low-power, and high-bandwidth memory is becoming more important. However, we are reaching the technical difficulty of achieving two-dimensional device scaling and computer architectures with off-chip memory. This article introduces a research progress on oxide-based 3D-integrated memory devices to break through this difficulty. In particular, the research on the memory devices using HfO2-based ferroelectrics as memory element and oxide semiconductor as channel material is discussed.

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  • Makoto Naruse, Atsushi Uchida
    Article type: Research Report
    2025 Volume 2025 Article ID: 250405
    Published: 2025
    Released on J-STAGE: February 08, 2025
    JOURNAL OPEN ACCESS

    The role of light is expanding beyond communication and measurement to include computing, as observed in the remarkable progress of artificial intelligence (AI) in the midst of the further digitization of society. This paper reviews the latest developments in photonic research aimed at enhancing reinforcement learning and decision-making tasks, both of which are fundamental functions of AI. We introduce methods for solving the multi-armed bandit problem using chaotic itinerancy of semiconductor laser dynamics and provide an overview of collective decision making that leverages quantum light interference.

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