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| Auteurs principaux: | , , , , , |
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| Format: | Preprint |
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2026
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| Accès en ligne: | https://arxiv.org/abs/2605.28171 |
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| _version_ | 1866918526771527680 |
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| author | Kubo, Yuuki Ishikawa, Takahiro Tanaka, Yuta Nakamoto, Yuki Sakata, Masafumi Tsuneyuki, Shinji |
| author_facet | Kubo, Yuuki Ishikawa, Takahiro Tanaka, Yuta Nakamoto, Yuki Sakata, Masafumi Tsuneyuki, Shinji |
| contents | We investigate the distorted face-centered-cubic (dfcc) phase of yttrium (Y) using a data-assimilation-based structure search that combines high-resolution powder x-ray diffraction (XRD) data with machine-learning interatomic potentials. By exploring supercells containing up to 128 atoms, we identify three low-enthalpy phases: the previously reported $I4_1/a$ structure and two additional structures, $Ibam$ and $R\overline{3}$. No data-assimilation-derived structure relaxes to the previously proposed $R\overline{3}m$ phase. Phonon calculations show that $I4_1/a$, $Ibam$, and $R\overline{3}$ are dynamically stable, whereas $R\overline{3}m$ exhibits imaginary modes near the $Γ$ point, indicating dynamical instability. Enthalpy calculations using both PBE and r$^{2}$SCAN place the four candidate structures within about 10 meV/atom, indicating a complex energy landscape with multiple competing minima, although $R\overline{3}m$ is consistently highest in enthalpy and r$^{2}$SCAN favors $I4_1/a$ throughout the dfcc pressure range. Rietveld refinements of the powder XRD profile at 60 GPa further narrow the viable structural models to $I4_1/a$ and $Ibam$, both of which reproduce the experimental data better than $R\overline{3}m$ and $R\overline{3}$. Taken together with the energetic ordering and dynamical stability, these results identify $I4_1/a$ as the most plausible structure of the dfcc phase of Y, with $Ibam$ remaining a close competing candidate, particularly toward the high-pressure side of the dfcc region. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2605_28171 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Search for high-pressure phases of yttrium via a data assimilation approach Kubo, Yuuki Ishikawa, Takahiro Tanaka, Yuta Nakamoto, Yuki Sakata, Masafumi Tsuneyuki, Shinji Materials Science We investigate the distorted face-centered-cubic (dfcc) phase of yttrium (Y) using a data-assimilation-based structure search that combines high-resolution powder x-ray diffraction (XRD) data with machine-learning interatomic potentials. By exploring supercells containing up to 128 atoms, we identify three low-enthalpy phases: the previously reported $I4_1/a$ structure and two additional structures, $Ibam$ and $R\overline{3}$. No data-assimilation-derived structure relaxes to the previously proposed $R\overline{3}m$ phase. Phonon calculations show that $I4_1/a$, $Ibam$, and $R\overline{3}$ are dynamically stable, whereas $R\overline{3}m$ exhibits imaginary modes near the $Γ$ point, indicating dynamical instability. Enthalpy calculations using both PBE and r$^{2}$SCAN place the four candidate structures within about 10 meV/atom, indicating a complex energy landscape with multiple competing minima, although $R\overline{3}m$ is consistently highest in enthalpy and r$^{2}$SCAN favors $I4_1/a$ throughout the dfcc pressure range. Rietveld refinements of the powder XRD profile at 60 GPa further narrow the viable structural models to $I4_1/a$ and $Ibam$, both of which reproduce the experimental data better than $R\overline{3}m$ and $R\overline{3}$. Taken together with the energetic ordering and dynamical stability, these results identify $I4_1/a$ as the most plausible structure of the dfcc phase of Y, with $Ibam$ remaining a close competing candidate, particularly toward the high-pressure side of the dfcc region. |
| title | Search for high-pressure phases of yttrium via a data assimilation approach |
| topic | Materials Science |
| url | https://arxiv.org/abs/2605.28171 |