Extreme Metastability of Diamond and its Transformation to the BC8 Post-Diamond Phase of Carbon.
J Phys Chem Lett
; 15(4): 1152-1160, 2024 Feb 01.
Article
em En
| MEDLINE
| ID: mdl-38269426
ABSTRACT
Diamond possesses exceptional physical properties due to its remarkably strong carbon-carbon bonding, leading to significant resilience to structural transformations at very high pressures and temperatures. Despite several experimental attempts, synthesis and recovery of the theoretically predicted post-diamond BC8 phase remains elusive. Through quantum-accurate multimillion atom molecular dynamics (MD) simulations, we have uncovered the extreme metastability of diamond at very high pressures, significantly exceeding its range of thermodynamic stability. We predict the post-diamond BC8 phase to be experimentally accessible only within a narrow high pressure-temperature region of the carbon phase diagram. The diamond to BC8 transformation proceeds through premelting followed by BC8 nucleation and growth in the metastable carbon liquid. We propose a double-shock compression pathway for BC8 synthesis, which is currently being explored in experiments at the National Ignition Facility.
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01-internacional
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MEDLINE
Idioma:
En
Ano de publicação:
2024
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Article