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A New Structure with Localized sp2 Bonding for Fivefold Twinning in Diamond
Yuying Yang1, Liu Feng2, Qiang Zhang1
1School of Chemistry and Chemical Engineering, Shandong University of Technology, Zibo, 255000, China.
Small (Weinheim an Der Bergstrasse, Germany)
|June 25, 2023
Summary
Diamond
Area of Science:
- Materials Science
- Nanotechnology
- Solid-State Physics
Background:
- Structural defects in diamond, like twin boundaries, significantly alter material properties.
- Atomic bonding changes from sp3 to sp2 hybridization occur at these defects.
Purpose of the Study:
- Investigate the atomic structure of fivefold twinning in detonation synthesized ultra-dispersed diamonds.
- Identify and analyze novel core structures within these fivefold twins.
Main Methods:
- Spherical aberration-corrected high-resolution electron microscopy (HREM).
- HREM image simulations.
- Molecular mechanics (MM) calculations.
Main Results:
- Two distinct fivefold twinning structures were observed in diamond.
- A new extended core structure featuring co-hybridization of sp3 and sp2 bonding was identified.
- The fundamental unit involves co-hybridized planar hexagonal carbon rings.
Conclusions:
- Fivefold twinning in diamond involves both sp3 and sp2 bonding configurations.
- The identified sp2-bonded hexagonal units are crucial structural elements in diamond grain boundaries.
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