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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.
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Calibrating experiments at atom-crushing pressures
Experimentalists can now generate terapascal pressures in the laboratory, conditions sufficient to alter the structure of atoms and the nature of interatomic bonding ( 1 ). These are the pressures of planets' interiors and origins—7 TPa at Jupiter's center, 4 TPa in the middle of Saturn, 0.36 TPa for Earth's inner core—and planet growth involves impacts that generate pressures into the terapascal range ( 2 ). Understanding materials and their properties at such conditions provides key insights into how planetary bodies form and then evolve over billions of years. On page 1063 of this issue, Fratanduono et al. ( 3 ) establish a new calibration for such experiments, and their pressure-volume relations for gold (Au) and platinum (Pt) can now serve as reliable standards to >1 TPa.
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- Award ID(s):
- 2020249
- PAR ID:
- 10332354
- Date Published:
- Journal Name:
- Science
- Volume:
- 372
- Issue:
- 6546
- ISSN:
- 0036-8075
- Page Range / eLocation ID:
- 1037 to 1038
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1126/science.abi8015
