Investigation of thermal and optical properties of perovskite materials by advanced phonon calculations

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K03424
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 13020:Semiconductors, optical properties of condensed matter and atomic physics-related
• Research Institution: National Institute for Materials Science
• Principal Investigator: Tadano Terumasa 国立研究開発法人物質・材料研究機構, 磁性・スピントロニクス材料研究センター, 主任研究員 (90760653)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 非調和効果 / フォノン / 構造相転移 / 第一原理計算 / 熱伝導率 / 光学特性

Outline of Final Research Achievements

We have developed a phonon calculation and finite temperature structure optimization method that can be used for material systems with strong anharmonicity of lattice vibrations. We have proposed a method to incorporate the frequency shift due to 3-phonon scattering, which is neglected in the conventional self-consistent phonon (SCP) method, under the quasiparticle approximation, and have successfully predicted the anharmonic phonon frequencies of perovskite materials with high fidelity. The effect of 4-phonon scattering on phonon linewidths and thermal conductivities was also investigated. Furthermore, we developed a finite temperature structure optimization method based on the quasi-harmonic approximation and the SCP method, and have successfully predicted the structural phase transitions and thermal expansion of ZnO and BaTiO3 with reasonable accuracy. These application studies demonstrated the effectiveness and versatility of the developed method.

Free Research Field

計算物質科学

Academic Significance and Societal Importance of the Research Achievements

開発した非調和フォノン計算・結晶構造最適化手法はペロブスカイト型材料に限らず多様な材料系へ適用可能であり、これまで困難だった有限温度物性計算への道を拓くものである。今後は太陽電池材料や光学デバイス、熱電変換材料への適用が進み、持続可能な社会構築に資する研究成果に繋がることが期待される。