Single crystal toroidal diamond anvils for high pressure experiments beyond 5 megabar

Area of Science:

• High-pressure physics and chemistry
• Planetary science
• Materials science

Background:

• Static compression experiments exceeding 4 megabars (Mbar) are rare but vital for fundamental physics and chemistry models.
• These high pressures are relevant for understanding planetary interiors and other extreme environments.
• Current methods for achieving such pressures are limited.

Purpose of the Study:

• To demonstrate the capability of focused ion beam crafted toroidal single-crystal diamond anvils for static compression.
• To achieve pressures over 5 Mbar using optimized diamond anvil cell (DAC) design.
• To explore the potential of these anvils for extending the accessible pressure range in DAC experiments.

Main Methods:

• Fabrication of toroidal single-crystal diamond anvils using focused ion beam milling.
• Utilizing anvils with approximately 9.0 μm culets.
• Employing rhenium (Re) as an in situ pressure marker for calibration.
• Performing static compression experiments in a diamond anvil cell.

Main Results:

• Successfully produced static pressures exceeding 5 Mbar.
• Reached a maximum pressure of approximately 6.15 Mbar.
• Demonstrated that the toroidal surface design prevents gasket outflow and stabilizes the central culet.
• Achieved pressures comparable to those typically accessed only by double-stage diamond anvils and dynamic compression platforms.

Conclusions:

• Focused ion beam crafted toroidal single-crystal diamond anvils are capable of generating ultra-high static pressures (>5 Mbar).
• The toroidal design offers significant advantages in pressure containment and stability.
• Optimizing single-crystal diamond anvil design is critical for advancing high-pressure research using diamond anvil cells.