1. Extreme Metastability of Diamond and its Transformation to BC8 Post-Diamond Phase of Carbon
- Author
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Nguyen-Cong, Kien, Willman, Jonathan T., Gonzalez, Joseph M., Williams, Ashley S., Belonoshko, Anatoly B., Moore, Stan G., Thompson, Aidan P., Wood, Mitchell A., Eggert, Jon H., Millot, Marius, Zepeda-Ruiz, Luis A., and Oleynik, Ivan I.
- Subjects
Condensed Matter - Materials Science - 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, multi-million 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 pre-melting followed by BC8 nucleation and growth in the metastable carbon liquid. We propose a double-shock compression pathway to achieve BC8 synthesis, which is currently being explored in theory-inspired experiments at the National Ignition Facility.
- Published
- 2024