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Using in situ atomic-resolution scanning transmission electron microscopy, atomic movements and rearrangements associated with diffusive solid to solid phase transformations in the Pt−Sn system are captured to reveal details of the underlying atomistic mechanisms that drive these transformations. In the PtSn4 to PtSn2 phase transformation, a periodic superlattice substructure and a unique intermediate structure precede the nucleation and growth of the PtSn2 phase. At the atomic level, all stages of the transformation are templated by the anisotropic crystal structure of the parent PtSn4 phase. In the case of the PtSn2 to Pt2Sn3 transformation, the anisotropy in the structure of product Pt2Sn3 dictates the path of transformation. Analysis of atomic configurations at the transformation front elucidates the diffusion pathways and lattice distortions required for these phase transformations. Comparison of multiple Pt−Sn phase transformations reveals the structural parameters governing solid to solid phase transformations in this technologically interesting intermetallic system.
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Pressure-Driven Solid–Solid Phase Transformations of Isotropic Particles Across Diverse Crystal Structure Types
This dataset accompanies the manuscript by H. Du, H. Pan, and J. Dshemuchadse,“Pressure-Driven Solid–Solid Phase Transformations of Isotropic Particles Across Diverse Crystal Structure Types”, in publication (2025). In this work, we investigated the influence of pressure on the behavior of 16 crystal structure types that have been shown to self-assemble in molecular dynamics simulations using isotropic, pairwise interaction potentials. We studied these diverse structures using a range of computational models as a function of pressure, characterized the high-pressure phases, identified four previously unknown crystal structure types, and categorized the observed phase transformations. This dataset includes the representative simulation trajectories (in .gsd file format) mentioned in the main text and the Supplemental Material. A README.txt file is included to assist with parsing the data. We hope that this dataset will be useful for future research on pressure-induced phase transformations in both experimental and simulation studies.
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- Award ID(s):
- 2144094
- PAR ID:
- 10573455
- Publisher / Repository:
- Materials Data Facility
- Date Published:
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract Investigating how solid matter behaves at enormous pressures, such as those found in the deep interiors of giant planets, is a great experimental challenge. Over the past decade, computational predictions have revealed that compression to terapascal pressures may bring about counter-intuitive changes in the structure and bonding of solids as quantum mechanical forces grow in influence 1–6 . Although this behaviour has been observed at modest pressures in the highly compressible light alkali metals 7,8 , it has not been established whether it is commonplace among high-pressure solids more broadly. We used shaped laser pulses at the National Ignition Facility to compress elemental Mg up to 1.3 TPa, which is approximately four times the pressure at the Earth’s core. By directly probing the crystal structure using nanosecond-duration X-ray diffraction, we found that Mg changes its crystal structure several times with non-close-packed phases emerging at the highest pressures. Our results demonstrate that phase transformations of extremely condensed matter, previously only accessible through theoretical calculations, can now be experimentally explored.more » « less
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