Diaphite-structured nanodiamonds with six- and twelve-fold symmetries

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Diaphite-structured nanodiamonds with six- and twelve-fold symmetries

Németh, P; McColl, K; Garvie, LAJ; Salzmann, CG; Pickard, CJ; Corà, F; Smith, RL; ... McMillan, PF; + view all (2021) Diaphite-structured nanodiamonds with six- and twelve-fold symmetries. Diamond and Related Materials , 119 , Article 108573. 10.1016/j.diamond.2021.108573. Green open access

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Abstract

Nanodiamonds (ND) with 1-5 nm dimensions found in meteorites or produced by chemical vapour deposition (CVD) and detonation synthesis are typically described in terms of an sp3-bonded carbon network. However, ultra-high-resolution transmission electron microscopy (uHRTEM) combined with density functional theory (DFT) modelling leads to a different structural interpretation. uHRTEM imaging and nanodiffraction studies of many NDs show six-fold symmetry features whose identity has long been controversial. We also observe diffraction patterns with twelve equally-spaced and symmetrically but unequally arranged reflections, indicating structures with crystallographically-forbidden ideal and distorted twelve-fold symmetry. Structural models based on our DFT calculations lead to an interpretation of these unusual features found throughout the meteoritic and CVD samples in terms of sp3 domains arranged around and coherently bonded to graphitic domains embedded within the diamond matrix. The bonding at the sp2-sp3 interface can explain the unusual features observed in electron energy-loss spectra (EELS) below the onset of the main diamond C1s core-loss edge leading to predictions of low-dimensional conductivity behaviour. The presence of sp2- as well as sp3-bonded regions allows us to interpret previously unexplained features of the Raman spectra and EELS data of ND materials.

Type:	Article
Title:	Diaphite-structured nanodiamonds with six- and twelve-fold symmetries
Open access status:	An open access version is available from UCL Discovery
DOI:	10.1016/j.diamond.2021.108573
Publisher version:	https://doi.org/10.1016/j.diamond.2021.108573
Language:	English
Additional information:	© 2021 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Keywords:	Nanodiamonds Diaphite Ultra-high-resolution TEM, Density functional calculations, Six - and twelve-fold symmetries, sp2 - and sp3 - bonded nanomaterials
UCL classification:	UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Chemistry UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy
URI:	https://discovery.ucl.ac.uk/id/eprint/10134199