Abstract
The phase behavior of carbon at high pressure and the search for carbon structures denser than diamond has been explored for decades showing large discrepancies, with many fundamental questions remaining unresolved. Here we show evidence of melting above the graphite-diamond-liquid (GDL) triple point (∼13 GPa, 4000 K) up to 50 GPa on samples recovered from single flash-heating events using spectroscopic and electron microscopic methods. The results show that for all pressures, diamond melts below the triple point temperature contradicting previous studies, most of which predict a positive slope of the melting curve.
| Original language | English |
|---|---|
| Pages (from-to) | 1-14 |
| Number of pages | 14 |
| Journal | High Pressure Research |
| Volume | 43 |
| Issue number | 1 |
| DOIs | |
| State | Published - 2023 |
Funding
This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan ( http://energy.gov/downloads/doe-public-access-plan ) . Acknowledgements This work was supported as part of Energy Frontier Research in Extreme Environments Center (EFree), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DE-SC0001057. BH and RB used resources at the High Flux Isotope Reactor and the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. D.G.M., B.H., R.B. and J.E.B would like to acknowledge the support from the Australian Research Council (ARC) Discovery Project scheme (DP170102087 and DP190101438). We thank C. Zhang for his help in the SEM operation and M. Somayazulu for his help with the Raman measurements, both at the Earth and Planets Laboratory, DC, USA. The authors gratefully acknowledge the scientific and technical assistance of the RMIT Microscopy & Microanalysis Facility, a linked laboratory of the Microscopy Australia.
| Funders | Funder number |
|---|---|
| Energy Frontier Research in Extreme Environments Center | |
| U.S. Department of Energy | |
| Office of Science | |
| Basic Energy Sciences | DE-SC0001057 |
| Oak Ridge National Laboratory | |
| Australian Research Council | DP190101438, DP170102087 |
| RMIT University |
Keywords
- Diamond cell
- diamond melting
- laser-heating