49P1-07Structural Insights into Thermal Conductivity of Amorphous Germanium Using Topological Data Analysis Yen-Ju Wu1, Kazuto Akagi2, Masahiro Goto3, and Yibin Xu1 1 Center for Basic Research on Materials, National Institute for Materials Science (NIMS) 2 Advanced Institute for Materials Research, Tohoku University 3 Research Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS) Amorphous materials are gaining industrial attention due to their unique thermal properties. Unlike crystalline materials, they exhibit distinct thermal and lattice vibration characteristics due to their lack of periodic atomic structure. However, analyzing atomic networks in transmission electron microscopy (TEM) images remains challenging. This study utilizes topological data analysis (TDA) and principal component analysis (PCA) on TEM images and molecular dynamics simulations of amorphous germanium (a-Ge) to uncover structural factors influencing thermal conductivity. Results indicate that larger atomic rings, formed at elevated deposition temperatures, improve heat transfer, offering a data-driven approach for designing optimized thermal insulators and thermoelectric materials through atomic network tailoring. [1] Y. Wu, K. Akagi, M. Goto, and Y. Xu, International Journal of Heat and Mass Transfer, 221, 125012 (2024). P1-08Structural Properties of Na2O-SiO2 Melts Under High Pressure, as Revealed by X-ray Diffraction and Molecular Dynamics Simulation Shino Hayafune1, Haruki Ichikawa1, Yohei Onodera2, Shinji Kohara2, Ken-ichi Funakoshi3, Tatsuya Sakamaki1, and Akio Suzuki1 1 Department of Earth Science, Graduate School of Science, Tohoku University 2 Center for Basic Research on Materials, National Institute for Materials Science (NIMS) 3 Neutron Science and Technology Center, Comprehensive Research Organization for Science and Society (CROSS) Clarifying the structure of silicate melts under high pressure is crucial for understanding properties such as the density and viscosity of magma in the Earth’s interior from a microscopic perspective. The present study aims at investigating the structure of Na2O–SiO2 melt under high pressure (2–5.4 GPa) using synchrotron radiation X-ray diffraction (XRD) experiments and classical molecular dynamics (MD) simulations. Energy-dispersive XRD measurements were conducted at the NE5C beamline of the PF-AR at KEK. MD simulations were performed in the NPT ensemble, using the LAMMPS code [1] The position of the First Sharp Diffraction Peak (FSDP) in the X-ray structure factor S(Q) shifted towards higher Q-values, and the height of the Second Sharp Diffraction Peak (SSDP) becomes more pronounced with increasing pressure. Analysis of the partial structure factors revealed that the contraction of Si–O network structure contribute to the shift of the FSDP. Moreover, it is found that the Na–O coordination number increases from 5.8 (2 GPa, 2000 K) to 7.0 (5 GPa, 2000 K), which is the origin of the evolution of SSDP. [1] A. P. Thompson et al., Comp. Phys. Comm., 271, 108171 (2022). Poster Award NomineePoster Award Nominee
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