Coherent interfaces govern direct transformation from graphite to diamond

Luo, Kun; Liu, Bing; Hu, Wentao; Dong, Xiao; Wang, Yanbin; Huang, Quan; Gao, Yufei; Sun, Ling; Zhao, Zhisheng; Wu, Yingju; Zhang, Yang; Ma, Mengdong; Zhou, Xiang-Feng; He, Jingliang; Yu, Dongli; Liu, Zhongyuan; Xu, Bin; Tian, Yongjun

doi:10.1038/s41586-022-04863-2

Cited by 111 publications

(124 citation statements)

References 50 publications

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“…These observations reveal that the incoherent interface between ND and DMG is generated by the GC-to-diamond transition. This incoherent interface is in strong contrast to the coherent interface caused by the graphite-to-diamond transition observed by HAADF-STEM 18 , and to the semicoherent interface (type 2 diaphite) in natural impact diamonds as observed by high-resolution transmission electron microscopy 18,21,22 . It also differs from the transient interface structure (with a graphitic interlayer distance that is actually less than 2.5 Å) that is from compressing multi-walled carbon nanotube fibres 23 .…”

Section: Microstructurementioning

confidence: 62%

Ultrastrong conductive in situ composite composed of nanodiamond incoherently embedded in disordered multilayer graphene

Wang

et al. 2022

Nat. Mater.

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Traditional ceramics or metals cannot simultaneously achieve ultrahigh strength and high electrical conductivity. The elemental carbon can form a variety of allotropes with entirely different physical properties, providing versatility for tuning mechanical and electrical properties in a wide range. Here, by precisely controlling the extent of transformation of amorphous carbon into diamond within a narrow temperature–pressure range, we synthesize an in situ composite consisting of ultrafine nanodiamond homogeneously dispersed in disordered multilayer graphene with incoherent interfaces, which demonstrates a Knoop hardness of up to ~53 GPa, a compressive strength of up to ~54 GPa and an electrical conductivity of 670–1,240 S m–1 at room temperature. With atomically resolving interface structures and molecular dynamics simulations, we reveal that amorphous carbon transforms into diamond through a nucleation process via a local rearrangement of carbon atoms and diffusion-driven growth, different from the transformation of graphite into diamond. The complex bonding between the diamond-like and graphite-like components greatly improves the mechanical properties of the composite. This superhard, ultrastrong, conductive elemental carbon composite has comprehensive properties that are superior to those of the known conductive ceramics and C/C composites. The intermediate hybridization state at the interfaces also provides insights into the amorphous-to-crystalline phase transition of carbon.

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Section: Microstructurementioning

confidence: 62%

Ultrastrong conductive in situ composite composed of nanodiamond incoherently embedded in disordered multilayer graphene

Wang

et al. 2022

Nat. Mater.

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“…The recently published work of Luo et al 12 presents experimental evidence of the hybrid sp 2 -sp 3 networks that are formed when graphite is transformed to diamond. The observed coherent interface structures display geometrical motifs that are very similar to the ones that we found in our simulations for supercells with diamond surfaces parallel to the [110] axis (see, for example, Figure 3 and Figures S2 and S3).…”

Section: Comparison With Experimental Resultsmentioning

confidence: 99%

“…Two interface structures between graphite and cubic diamond, called Gradia-CO and Gradia-CA, are distinguished in ref . The interface morphology depends strongly on the orientation of the diamond surfaces that directly decide the configuration of connecting atoms.…”

Section: Resultsmentioning

confidence: 99%

“…The temperature threshold for graphitization can be reduced by the use of a metal catalyst such as Ni . Graphene-diamond mixed structures also appear in a variety of other conditions, e.g., during epitaxial growth of diamond on graphite edges, in stretched diamond nanopillars, in polished (110) textured diamond plates, in high-pressure high-temperature experiments, or between (113) diamond surfaces in polycrystalline samples . Carbon nanostructures with sp 2 -sp 3 bonds were also observed in shock-formed meteorite and naturally or laboratory-shocked samples …”

Section: Introductionmentioning

confidence: 99%

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Prediction and Characterization of Graphitic Structures at Diamond Grain Boundaries

2022

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Diamond−graphene interfaces with admixtures of sp 2and sp 3 -hybridized bonds have been drawing increasing attention because of their potential for applications in electronic devices. In this work we investigate the formation of sp 2 -bonded domains included within sp 3 -bonded diamond structures, more specifically at 23 different low-energy diamond grain boundaries with 21 distinct surface orientations. To this end, we rely on an efficient constrained global-structure prediction algorithm, using energy and forces from density-functional theory and density-functional tight-binding, to identify low-energy interface reconstructions at grain boundaries. Our extensive simulations show that graphitic networks always stem from flattening and reconstruction of corrugated hexagonal layers with (111) orientation. The most stable sp 2 insertions are found between parallel diamond surfaces. When these surfaces contain a ⟨110⟩ axis, we distinguish two classes of recurring reconstructions, while only one type is observed for diamond surfaces containing a ⟨100⟩ axis. We also study mixed sp 2 -and sp 3 -bonds as insertions at tilt grain boundaries, where bond distortion and bending of the graphitic planes, constrained by the grain geometry, have destabilizing effects. Finally, we study the electronic properties of these structures. While graphene adsorbed on diamond has usually a finite band gap, mixed diamond−graphene phases are mostly metallic, with localized states at the edges of the graphene-like stripes.

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“…Weak van der Waals forced graphite of sp 2 carbon hybridization offers a two-dimensional (2D) graphene single layer by micromechanical manipulation. , The single-layer graphene exhibits an anomalous half-integer quantum Hall effect with gapless Dirac cones. , Recently, stacking and twisting the two graphene layers under a magic angle of almost 1.1° result in the bilayer graphene superlattice achieving intrinsic unconventional superconductivity. , More importantly, sp 2 hybrid graphite is used as the famous precursor for typical sp 3 carbon allotropes. The graphite single crystals undergo diverse transformations to diamond, nanotwinned and lonsdaleite diamonds, and amorphous carbon. − However, extreme conditions such as a high temperature of over 1000 °C and a high pressure of over 20 GPa are usually demanded to overcome the chemical reaction energy barriers from graphite.…”

Section: Introductionmentioning

confidence: 99%

Atomic-Scale Pentagraphene Ribbons Stabilized with Alkali Metals under Moderate Pressures

et al. 2022

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Pentagraphene frameworks with sp 2 carbon atoms have significance in fundamental research studies and material science. Here, we find pentagon ribbons stacked in an AB sequence at the atomic scale within alkali metal atoms. A Pnma phase is favored on the Gibbs free energy landscape at moderate pressures and finite temperatures. Strong electron localization, covalent interactions, weak van der Waals interactions, and electronic repulsive interactions coexist in this ionic structure. Electronic bands with narrow direct gaps are flattened with double degeneracy to produce a small effective mass and van Hove singularity for the density of states, which enhances visible-light absorption and produces a thermoelectric power factor on crystals. Alkali metal atoms strongly scatter acoustic−optical phonons to reduce the lattice thermal conductivity to an ultralow level. These characteristics introduce potential thermoelectric effects into Pnma crystals. In addition, the alkali metal ions exhibit high delocalizations with superionic properties at high temperatures.

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Coherent interfaces govern direct transformation from graphite to diamond

Cited by 111 publications

References 50 publications

Ultrastrong conductive in situ composite composed of nanodiamond incoherently embedded in disordered multilayer graphene

Ultrastrong conductive in situ composite composed of nanodiamond incoherently embedded in disordered multilayer graphene

Prediction and Characterization of Graphitic Structures at Diamond Grain Boundaries

Atomic-Scale Pentagraphene Ribbons Stabilized with Alkali Metals under Moderate Pressures

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