Stability of numerous novel potassium chlorides at high pressure
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2016-05-23 |
| Journal | Scientific Reports |
| Authors | Weiwei Zhang, Artem R. Oganov, Qiang Zhu, Sergey S. Lobanov, Elissaios Stavrou |
| Institutions | Carnegie Institution for Science, Geophysical Laboratory |
| Citations | 32 |
| Analysis | Full AI Review Included |
Technical Documentation & Analysis: High-Pressure Synthesis of Novel Potassium Chlorides
Section titled âTechnical Documentation & Analysis: High-Pressure Synthesis of Novel Potassium ChloridesâThis document analyzes the research paper âStability of numerous novel potassium chlorides at high pressureâ (Sci. Rep. 6, 26265) to identify critical material requirements and demonstrate how 6CCVDâs specialized MPCVD diamond products (SCD/PCD) provide essential solutions for high-pressure research and synthesis.
Executive Summary
Section titled âExecutive SummaryâThis research successfully synthesized novel, thermodynamically stable potassium chloride compounds (e.g., KCl3, K3Cl5, KCl7) under extreme conditions, revealing a surprisingly rich chemistry in a seemingly simple system.
- Core Achievement: Experimental verification of theoretically predicted high-pressure phases (P3c1-KCl3 and Pm3n-KCl3) using a laser-heated Diamond Anvil Cell (LH-DAC).
- Extreme Conditions: Synthesis required pressures up to 70 GPa and temperatures exceeding 2000 K.
- Material Requirement: The experiment relies critically on high-purity, optical-grade Single Crystal Diamond (SCD) anvils capable of withstanding extreme mechanical stress while maintaining transparency for laser heating (1064 nm) and spectroscopic analysis (Raman/XRD).
- Novel Phases: Discovery of metallic (Kn+1Cln homologs) and insulating (KCl3) phases, some exhibiting 2D-metallic character at the antiphase boundaries.
- Methodology: Combined quantum-mechanical variable-composition evolutionary simulations (USPEX) with in situ synchrotron X-ray diffraction (XRD) and Raman spectroscopy.
- 6CCVD Value Proposition: 6CCVD provides the necessary high-quality, custom-dimensioned SCD plates and anvils, polished to ultra-low roughness (Ra < 1 nm), essential for replicating and extending this frontier research.
Technical Specifications
Section titled âTechnical SpecificationsâThe following hard data points were extracted from the research paper, highlighting the extreme conditions and material properties achieved or required.
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Maximum Pressure (Synthesis) | 70 | GPa | Laser-heated DAC experiment |
| Synthesis Temperature | > 2000 | K | Laser heating required to overcome kinetic barriers |
| DAC Culet Size | 300 | ”m | Symmetrical DAC geometry |
| Gasket Hole Diameter | 70-80 | ”m | Sample chamber size in Re gasket |
| X-ray Beam Size (Mapping) | 2-3 | ”m | Used for mapping quenched samples |
| X-ray Wavelengths | 0.3100, 0.3344 | Ă | Synchrotron XRD analysis |
| Raman Excitation Wavelengths | 488 or 532 | nm | Solid state laser lines used for spectroscopy |
| DFT Band Gap (P31m-KCl3) | 2.60 | eV | Semiconductor phase at 1 atm, 0 K |
| DFT Band Gap (P3c1-KCl3) | 1.78 | eV | Semiconductor phase at 20 GPa |
| Metallization Pressure (P3c1-KCl3) | > 160 | GPa | Pressure required for band gap closure |
Key Methodologies
Section titled âKey MethodologiesâThe experimental verification of novel K-Cl phases relied on precise control of pressure, temperature, and material purity within the DAC environment.
- Theoretical Prediction (USPEX): Quantum-mechanical variable-composition evolutionary simulations were used to predict stable compounds (K3Cl, K2Cl, KCl3, etc.) and their corresponding crystal structures across a pressure range of 1 atm to 300 GPa.
- Sample Preparation: KCl single crystal platelets (8-15 ”m thick) were cleaved and stacked in a Rhenium (Re) gasket with empty space (5-15 ”m) for chlorine condensation.
- Chlorine Loading: DACs were cooled to 77 K (liquid nitrogen) in a nitrogen-purged glove box, and high-purity chlorine gas (>99.8%) was injected into the gasket cavity via a capillary.
- High-Pressure/High-Temperature Synthesis: Static pressures up to 70 GPa were generated using symmetrical DACs. Samples were laser-heated using a 1064 nm fiber laser to temperatures exceeding 2000 K.
- Characterization (In Situ):
- Synchrotron XRD: Used to identify phase transformations (e.g., P3c1-KCl3 and Pm3n-KCl3) at high pressure and temperature.
- Raman Spectroscopy: Used to analyze vibrational modes, confirming the presence of the synthesized compounds (e.g., 15 peaks observed for P3c1-KCl3).
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & CapabilitiesâThe successful execution of high-pressure synthesis and in situ characterization, particularly in a laser-heated DAC (LH-DAC) setup, is fundamentally dependent on the quality and optical properties of the diamond anvils. 6CCVD is uniquely positioned to supply the specialized MPCVD diamond required for this demanding research.
Applicable Materials
Section titled âApplicable MaterialsâTo replicate or extend this high-pressure research, the following 6CCVD materials are essential:
| 6CCVD Material | Specification | Application in Research |
|---|---|---|
| Optical Grade SCD | Type IIa, Ultra-low Nitrogen Content | Essential for DAC anvils. High purity ensures minimal absorption of the 1064 nm heating laser and maximum transparency for X-ray and Raman analysis (488/532 nm). |
| High-Purity SCD Plates | Thickness: 100 ”m - 500 ”m | Starting material for custom anvil fabrication, ensuring mechanical integrity up to 70 GPa and beyond. |
| BDD (Boron-Doped Diamond) | Custom Doping Levels | While not used in this specific study, BDD is critical for future extensions requiring in situ electrical conductivity measurements of the predicted metallic phases (Kn+1Cln). |
Customization Potential
Section titled âCustomization PotentialâThe precision required for DAC experimentsâfrom culet size to optical alignmentâdemands highly customized diamond components. 6CCVDâs in-house capabilities directly address these needs:
- Custom Dimensions and Geometry: 6CCVD provides SCD plates and wafers up to 125 mm, with the ability to laser-cut and shape anvils to precise specifications (e.g., 300 ”m culets, specific bevels, and girdle diameters).
- Ultra-Precision Polishing: The quality of the anvil interface is paramount for achieving high pressure and maintaining optical clarity. 6CCVD guarantees ultra-low surface roughness:
- SCD: Ra < 1 nm
- Inch-size PCD: Ra < 5 nm
- Advanced Metalization Services: For future experiments involving electrical measurements of the predicted 2D-metallic phases or integrated resistive heating elements, 6CCVD offers custom metalization layers (Au, Pt, Pd, Ti, W, Cu) directly patterned onto the diamond surface.
Engineering Support
Section titled âEngineering SupportâThe synthesis of novel materials under extreme conditions, such as the high-pressure K-Cl system, requires deep expertise in material science and high-pressure physics.
- 6CCVDâs in-house PhD team specializes in the properties and applications of MPCVD diamond. We offer consultation on material selection, geometry optimization, and purity requirements necessary for similar High-Pressure Synthesis and Spectroscopy projects.
- We ensure that the SCD material supplied is optimized for the specific laser wavelengths (1064 nm for heating, 488/532 nm for Raman) and X-ray transparency required by synchrotron facilities (APS, DESY).
Call to Action: For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.