Profound Softening and Shear-Induced Melting of Diamond at Extreme Conditions: An ab-initio Molecular Dynamics Study
Document Type
Article
Publication Date
8-28-2019
Publication Title
Carbon
Volume
155
First page number:
361
Last page number:
368
Abstract
Diamond retains original crystal form and large elastic stiffness up to very high temperatures, and strengthens considerably under high pressures. These remarkable characters dictate its behaviors under extreme loadings such as those in laser-heated diamond anvil cells (LHDACs) or giant planetary interiors. Here we report surprising findings from ab initio molecular dynamics simulations revealing that diamond's mechanical strengths reduce precipitously at elevated temperatures, by 50% at 3000 K, despite that its elastic parameters remain little changed. Our results also unravel an extraordinary shear-induced reduction of melting temperature of diamond under (111)[112] shear strains by as much as 1150 K, greatly altering its pressure-temperature (p−T) phase diagram when shear deformations exist. These new benchmarks offer crucial insights for elucidating extreme mechanics of diamond at high p-T conditions, advancing fundamental knowledge with major implications for LHDAC operation and planetary modeling.
Disciplines
Biological and Chemical Physics
Language
English
Repository Citation
Wen, L.,
Wu, H.,
Sun, H.,
Chen, C.
(2019).
Profound Softening and Shear-Induced Melting of Diamond at Extreme Conditions: An ab-initio Molecular Dynamics Study.
Carbon, 155
361-368.
http://dx.doi.org/10.1016/j.carbon.2019.08.079