Phys.org March 18, 2024 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, an international team of researchers (USA – University of South Florida, Los Alamos National Laboratory, Lawrence Livermore National Laboratory, Sweden) uncovered the extreme metastability of diamond at very high pressures, significantly exceeding its range of thermodynamic stability. They predicted 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 proceeded through premelting followed by BC8 nucleation and […]
Category Archives: Diamond
Supercomputers have revealed the giant ‘pillars of heat’ funneling diamonds upward from deep within Earth
Phys.org May 9, 2023 Most diamonds have been transported to Earth’s surface from depths between ~120 km and ~660 km by volatile-rich magmas called kimberlites. The reconstructed locations of kimberlites erupted in the past 320 million years have been shown to be correlated with seismically imaged large basal mantle structures at ~2,800 km depth. This correlation has been interpreted as requiring basal mantle structures to be stationary over time. However, the geodynamic process responsible for this correlation remains to be identified. Researchers in Australia developed global mantle convection models including a basal layer of dense material and driven by surface plate motions to […]