Synthesis of paracrystalline diamond
Hu Tang1, Xiaohong Yuan1, Yong Cheng2
1Center for High Pressure Science and Technology Advanced Research, Beijing, China.
Nature
|November 25, 2021
Summary
Researchers discovered a new paracrystalline state of diamond, distinct from crystalline or amorphous forms. This novel diamond material, synthesized under high pressure, bridges the gap between ordered and disordered solids.
Area of Science:
- Materials Science
- Solid-State Physics
- Nanotechnology
Background:
- Solids are classified as crystalline (long-range order) or non-crystalline (amorphous).
- Distinguishing between these states becomes challenging with reduced long-range order in crystals.
- A fundamental gap exists in understanding structures between fully crystalline and amorphous states.
Purpose of the Study:
- To report the discovery of a novel paracrystalline state of diamond.
- To characterize the unique structural properties of this paracrystalline diamond.
- To investigate the formation mechanism and potential applications of this new material.
Main Methods:
- Synthesis of paracrystalline diamond from face-centred cubic C60 under high-pressure, high-temperature conditions (30 GPa, 1600 K).
- Structural characterization using X-ray diffraction and high-resolution transmission electron microscopy.
- Analysis of structural properties and formation mechanisms via advanced molecular dynamics simulations.
Main Results:
- Identification of a paracrystalline diamond state characterized by sub-nanometre paracrystallites with medium-range order.
- Demonstration of distinct structural properties compared to crystalline and amorphous diamond.
- Elucidation of formation mechanisms involving nucleation sites in compressed C60 and sp3 bonding.
Conclusions:
- The discovery of paracrystalline diamond introduces a new form within the carbon family with unique properties.
- This finding represents a crucial link between amorphous and crystalline structures, expanding our understanding of material states.
- Paracrystalline diamond holds potential for the development of novel advanced materials.
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