Pressure-induced structural transitions of diamond (100) surfaces

Area of Science:

• Materials Science
• Surface Science
• Computational Chemistry

Background:

• Extensive research exists on bulk crystalline solids under pressure.
• Solid surfaces transmitting pressure have been comparatively understudied.
• Understanding surface behavior is crucial for materials under extreme conditions.

Purpose of the Study:

• Investigate pressure-induced structural transitions of the diamond (100) surface.
• Identify and characterize different surface configurations under pressure.
• Determine the most stable diamond (100) surfaces at varying pressures and temperatures.

Main Methods:

• Utilized molecular dynamics simulations.
• Employed the volume-Constant Pressure Molecular Dynamics method for finite systems.
• Conducted an exhaustive search for dimerized configurations, considering symmetries.

Main Results:

• Identified eight distinct, nearly energy-degenerate diamond (100) surfaces at zero pressure.
• Observed increasing energy differences between surfaces under high external pressure.
• Indicated pressure-induced graphitization of surfaces at finite temperatures, with varying transition pressures.

Conclusions:

• Constructed a pressure-temperature (P-T) phase diagram illustrating surface stability and transitions.
• Provided a theoretical foundation for diamond utilization under high pressure.
• Offered insights into the surface properties of materials subjected to extreme conditions.