# Fileset [Supplementary Information Ti3MSiO LiZhijun_MDR.docx](https://mdr.nims.go.jp/filesets/84ed1db0-33d4-4e9b-ac37-3890c094eba5/download) ## Creator [Zhijun Li](https://orcid.org/0009-0006-6314-410X), Xun Kang, [Xuan Liang](https://orcid.org/0000-0002-1062-4103), [Alexei A. Belik](https://orcid.org/0000-0001-9031-2355), [Masao Arai](https://orcid.org/0000-0003-0088-5649), [Kazunari Yamaura](https://orcid.org/0000-0003-0390-8244), Rintaro Oshikiri, Asuka Ishikawa, Takafumi D. Yamamoto, Shintaro Suzuki, Ryuji Tamura ## Rights This document is the Accepted Manuscript version of a Published Work that appeared in final form in Inorganic Chemistry, copyright © 2025 American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acs.inorgchem.4c05010.[In Copyright](http://rightsstatements.org/vocab/InC/1.0/) ## Other metadata [Crystal Structure and Physical Properties of Au4Al-Type Suboxides in the Ti–Rh–Si–O and Ti–Ir–Si–O Systems](https://mdr.nims.go.jp/datasets/ae5afc42-35d3-47d1-887d-67aec3f2843c) ## Fulltext Supplementary informationCrystal Structure and Physical Properties of Au4Al-Type Suboxides in the Ti-Rh-Si-O and Ti-Ir-Si-O SystemsZhijun Li,1,2,* Xun Kang,1,2 Xuan Liang,1,2 Alexei A. Belik,1 Masao Arai,3 Kazunari Yamaura1,2,* Rintaro Oshikiri,4 Asuka Ishikawa,4 Takafumi D. Yamamoto,4 Shintaro Suzuki,4,# Ryuji Tamura 41 Research Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan2 Graduate School of Chemical Sciences and Engineering, Hokkaido University, North 10 West 8, Kita-ku, Sapporo, Hokkaido 060-0810, Japan3 Center for Basic Research on Materials, National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan4 Department of Materials Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, JapanCorresponding Author* Zhijun Li and Kazunari YamauraQuantum Solid State Materials GroupResearch Center for Functional MaterialsNational Institute for Materials Science1-1-Namiki, Tsukuba, Ibaraki 305-0044, JapanTEL: +81-29-860-4658E-mail: Li.Zhijun@nims.go.jp and YAMAURA.Kazunari@nims.go.jpPresent Address# Shintaro SuzukiDepartment of Physical Sciences, College of Science and Engineering, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa 252-5258, Japan Figure S1: Lattice parameter a of the cubic phase for samples with nominal compositions Ti88Rh34Si24-x(SiO2)x, plotted as a function of x. The data show that the lattice parameter remains relatively constant across varying oxygen contents, indicating that oxygen introduction has minimal impact on the cubic lattice parameter. The dashed red line serves as a visual guide to the trend. Figure S2: X-ray diffraction patterns of Ti3MSiO (M = Rh, Rh0.5Ir0.5, Ir) measured using Cu-Kα radiation. The experimental data (colored lines) for all three samples show strong agreement with the calculated patterns (not displayed), confirming the formation of the cubic phase. Figure S3: Temperature dependence of the lattice parameter and unit cell volume for cubic Ti3RhSiO. (a) The lattice parameter a shows gradual thermal expansion with increasing temperature. (b) The unit cell volume V (red circles) and the thermal expansion coefficient (blue diamonds) both increase with temperature up to 800 K. Figure S4: Density of States (DOS) for Ti3MSiO compounds (M = Co, Rh, Ir) as a function of energy. The plots show the distribution of electronic states near the Fermi level (set at 0 eV) for Co, Rh, and Ir substitutions. Systematic variations in the DOS near the Fermi level are observed across the compounds, including notable drops resembling a quasi-gap. Note that the compound with M = Co has not been experimentally confirmed or synthesized in this study. The calculations were performed using the projector augmented wave method implemented in the Vienna Ab initio Simulation Package (VASP).1,2 The generalized gradient approximation (GGA) of density functional theory, with the Perdew-Burke-Ernzerhof exchange-correlation functional, was employed.3 Structural optimization was conducted by fully relaxing the cell shape and internal atomic coordinates based on the calculated stress and atomic forces. DOS were subsequently computed for the optimized structure.References:(1) Kresse, G.; Furthmüller, J. Efficiency of Ab-Initio Total Energy Calculations for Metals and Semiconductors Using a Plane-Wave Basis Set. Comput Mater Sci 1996, 6 (1), 15–50. https://doi.org/10.1016/0927-0256(96)00008-0.(2) Kresse, G.; Joubert, D. From Ultrasoft Pseudopotentials to the Projector Augmented-Wave Method. Phys Rev B 1999, 59 (3), 1758–1775. https://doi.org/10.1103/PhysRevB.59.1758.(3) Perdew, J. P.; Burke, K.; Ernzerhof, M. Generalized Gradient Approximation Made Simple. Phys Rev Lett 1996, 77 (18), 3865–3868. https://doi.org/10.1103/PhysRevLett.77.3865.S2image1.tiffimage2.tiffimage3.tiffimage4.png