2020/02/10 by Jiajun Dong, Zhen Yao, Mingguang Yao +8 · 69 citations
Earth and Planetary Sciences · Materials Science · Medicine · #Carbon Nanotubes in Composites #Composite material #Decompression #Diamond #Diamond and Carbon-based Materials Research #Graphite #High pressure #High-pressure geophysics and materials #Materials science #Mechanics #Medicine #Physics #Surgery
paper · doi:10.1103/physrevlett.124.065701
published in Physical Review Letters 124(6), 065701 (American Physical Society)
openalex publication_date 2020/02/10 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
Graphite is known to transform into diamond under dynamic compression or under combined high pressure and high temperature, either by a concerted mechanism or by a nucleation mechanism. However, these mechanisms fail to explain the recently reported discovery of diamond formation during ambient temperature compression combined with shear stress. Here we report a new transition pathway for graphite to diamond under compression combined with shear, based on results from both theoretical simulations and advanced experiments. In contrast to the known model for thermally activated diamond formation under pressure, the shear-induced diamond formation takes place during the decompression process via structural transitions. At a high pressure with large shear, graphite transforms into ultrastrong sp3 phases whose structures depend on the degree of shear stress. These metastable sp3 phases transform into either diamond or graphite upon decompression. Our results explain several recent experimental observations of low-temperature diamond formation. They also emphasize the importance of shear stress for diamond formation, providing new insight into the graphite-diamond transformation mechanism.