Structure and properties of diamond-like phase obtained from tetragonal graphene layers
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2016-01-01 |
| Journal | Letters on Materials |
| Authors | V. A. Greshnyakov, E. A. Belenkov |
| Institutions | Chelyabinsk State University |
| Citations | 4 |
| Analysis | Full AI Review Included |
Technical Analysis and Commercial Summary: Novel LA10 Diamond-Like Phase
Section titled âTechnical Analysis and Commercial Summary: Novel LA10 Diamond-Like Phaseâ6CCVD Reference ID: Greshnyakov_LA10_2016
This document analyzes the theoretical properties of the LA10 carbon phase, a predicted diamond-like material derived from polymerized tetragonal graphene layers, and connects the findings to 6CCVDâs expertise in customized MPCVD diamond synthesis for high-performance applications.
Executive Summary
Section titled âExecutive SummaryâThe research details the calculated structure and properties of a novel carbon phase (LA10) exhibiting diamond-like characteristics, derived theoretically via Density Functional Theory (DFT) modeling of specific tetragonal graphene layer polymerization.
- Novel Structure: The LA10 phase adopts a body-centered tetragonal crystal lattice ($I4_{1}/amd$ space group), distinct from conventional cubic diamond.
- Exceptional Mechanical Performance: Predicted Knoop Hardness ($H_{K}$) is 72.3 GPa, positioning it among superhard materials, comparable to boron carbide ($B_{4}C$).
- Wide-Gap Semiconductor Potential: Calculated band gap ($E_{g}$) ranges from 5.0 eV to 6.1 eV, confirming its potential utility in high-power electronics and deep-UV optics.
- Stability: The LA10 structure is predicted to be stable under normal conditions, with its sublimation energy only 6.9% less than that of cubic diamond.
- Synthesis Route: The most probable experimental route suggested is the strong static compression of specific polymorphic tetragonal graphite layers.
- Strategic Application: The materialâs combination of extreme hardness and wide band gap makes it highly relevant for advanced abrasive technologies and next-generation electronic devices.
Technical Specifications
Section titled âTechnical SpecificationsâThe following physical and electronic properties were theoretically calculated for the LA10 diamond-like phase using the DFT-GGA methodology.
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Crystal System | Tetragonal | N/A | Space Group $I4_{1}/amd$ |
| Lattice Parameter (a) | 3.581 | Ă | Unit cell dimension |
| Lattice Parameter (c) | 8.611 | Ă | Unit cell dimension |
| Atoms per Unit Cell (Z) | 16 | atoms | Body-centered unit cell |
| Knoop Hardness (HK) | 72.3 | GPa | High strength characteristic |
| Bulk Modulus (B) | 351 | GPa | Measure of material stiffness |
| Band Gap (Eg) Range | 5.0 to 6.1 | eV | Wide-gap semiconductor classification |
| Density (Ï) | 2.890 | g/cm3 | Calculated mass density |
| Sublimation Energy (Esub) | 7.34 | eV/atom | Only 6.9% less than cubic diamond |
| Shortest Bond Length (L1) | 1.5181 | Ă | Covalent C-C bond length |
| Longest Bond Length (L4) | 1.5798 | Ă | Covalent C-C bond length |
Key Methodologies
Section titled âKey MethodologiesâThe theoretical analysis relies on the Density Functional Theory (DFT) approach using the Generalized Gradient Approximation (GGA).
- Fundamental Theoretical Framework: DFT employed in the Generalized Gradient Approximation (GGA).
- Exchange-Correlation Functional: Perdew-Burke-Ernzerhof (PBE) functional utilized for calculation of sublimation energy, band structure, and electronic density of states (DOS).
- Geometric Optimization: Structures optimized using the Conjugate Gradients method.
- Convergence Criteria: Optimization proceeded until atomic forces were less than 1.5 meV/Ă .
- Brillouin Zone Integration: Used a k-point mesh of 10x10x10.
- Plane-Wave Basis Set Cutoff: Energy cutoff ($E_{\text{cutoff}}$) set at 800 eV.
- Mechanical Property Calculation: Bulk modulus calculated from volume changes up to 3%. Hardness calculated via empirical methodology.
- X-Ray Diffraction (XRD) Simulation: Theoretical powder X-ray diffraction patterns were calculated using structural parameters derived from DFT-GGA, simulating a standard Cu-Kα source ($\lambda_{\text{Cu-K}\alpha} = 1.5405 \text{ à }$).
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & CapabilitiesâThe theoretical prediction of the LA10 phase reinforces the extreme performance potential of four-coordinated carbon structures. 6CCVD is uniquely positioned to supply the foundational materials necessary to replicate, test, and extend research into superhard wide-bandgap carbon structures, including analogous Silicon (Si) or Silicon Carbide (SiC) phases mentioned in the conclusion.
Applicable Materials for Replication and Extension
Section titled âApplicable Materials for Replication and ExtensionâTo advance research targeting the LA10 phaseâs predicted applications (abrasives, wide-gap electronics), 6CCVD provides precision MPCVD materials optimized for these extreme requirements:
| LA10 Property Target | 6CCVD Recommended Material | Rationale & Capability |
|---|---|---|
| Extreme Hardness (72.3 GPa) | High-Wear Polycrystalline Diamond (PCD) | High-density PCD up to 125mm in diameter serves as the industry standard for extreme abrasive and cutting applications. |
| Wide Band Gap (5.0-6.1 eV) | High-Purity Single Crystal Diamond (SCD) | Our SCD offers unmatched material purity and controlled crystal orientation, ideal for developing wide-bandgap semiconductor devices, optical detectors, and high-power electronics. |
| Si/SiC Analogous Research | Custom Thin-Film SCD/PCD Substrates | SCD thicknesses from 0.1 ”m up to 500 ”m are available for heteroepitaxial growth experiments, essential for stabilizing novel carbon or analogous structures on existing semiconductor platforms. |
| High Compression Studies | Thick Substrate Grade Diamond | Substrates up to 10mm thick can withstand the high-pressure environments (e.g., static compression of graphite) required for experimental synthesis of novel phases like LA10. |
Customization Potential for Novel Structure Synthesis
Section titled âCustomization Potential for Novel Structure SynthesisâExperimental confirmation of phases synthesized under extreme conditions requires highly tailored analysis platforms. 6CCVD offers specialized fabrication services critical for characterizing these materials:
- Custom Dimensions and Etching: We provide custom laser cutting and shaping for plates and wafers up to 125mm (PCD). If the LA10 phase is synthesized as a thin film or requires micro-structural analysis, 6CCVD can etch precise measurement features.
- Surface Preparation: Achieving a stable interface, especially if LA10 is synthesized on a substrate (as suggested by the reference to Si/SiC), requires exceptional surface quality. We offer:
- SCD Polishing: Surface roughness $R_{a} < 1 \text{ nm}$.
- Inch-size PCD Polishing: Surface roughness $R_{a} < 5 \text{ nm}$.
- Advanced Metalization Services: Should the research transition to electronic device fabrication (taking advantage of the 5.0-6.1 eV band gap), 6CCVD offers in-house deposition of standard and custom metal contacts, including Au, Pt, Pd, Ti, W, and Cu, crucial for optimizing contact resistance in wide-bandgap semiconductors.
Engineering Support & Global Logistics
Section titled âEngineering Support & Global Logisticsâ6CCVDâs in-house PhD engineering team specializes in diamond material science and can assist researchers in selecting the optimal material properties (purity, doping, orientation) required to replicate or extend high-pressure synthesis projects similar to the LA10 study.
We ensure rapid delivery of custom, high-specification CVD diamond products worldwide, offering DDU (Delivered Duty Unpaid) as default and DDP (Delivered Duty Paid) options for seamless international logistics.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
Using the density functional theory method in the generalized gradient approximation in this article, crystal structure and properties of the carbon diamond-like LA10 phase, in which all the atomic positions are crystallographically equivalent, were calculated. The diamond-like LA10 phase structure can be theoretical derived by polymerization of tetragonal L4-8 graphene layers, consisting of fourmembered and eightmembered structural units. The LA10 crystalline phase lattice belongs to a tetragonal crystal system with I41/amd space group symmetry. The body-centered tetragonal unit cell has the following parameters: a = 3.581 Ă , c = 8.611 Ă , and Z = 16 atoms. Band structure and electron density of states calculations showed that the diamond-like LA10 phase is a wide-gap semiconductor with a band gap of 5.0 eV to 6.1 eV. Furthermore, the LA10 phase should have high strength characteristics: the Knoop hardness is equal to 72.3 GPa, the bulk modulus is 351 GPa. It is also established that the LA10 phase should be stable under normal conditions, as the sublimation energy of this phase is only 6.9% less than the corresponding energy of cubic diamond. The most probable synthetic way to obtain the LA10 phase is a strong static compression of graphite, consisting of tetragonal polymorphic variety graphene, perpendicular to the graphene layers. This diamond-like phase can be experimentally identified by a theoretical powder X-ray diffraction pattern, calculated in this work. The calculated X-ray pattern is quite different from the X-ray patterns cubic diamond and lonsdaleite, but is very close to the X-ray pattern hexagonal graphite.