Pressure apparatus of split-octahedron type for x-ray diffraction studies

Area of Science:

• Materials Science
• Condensed Matter Physics
• High-Pressure Physics

Background:

• Studying materials under extreme pressure is crucial for understanding their fundamental properties.
• X-ray diffraction is a key technique for probing material structure, but high-pressure environments pose significant experimental challenges.

Purpose of the Study:

• To develop and validate a new apparatus for X-ray diffraction analysis at ultra-high pressures.
• To accurately determine the pressure-induced semiconductor-to-metal transition points for various semiconductor materials.

Main Methods:

• Designed a split-octahedron apparatus with a multistaged arrangement for high-pressure generation.
• Utilized a diamond powder and epoxy resin mixture as a pressure-transmitting medium.
• Simultaneously monitored electrical resistance and lattice parameters (using NaCl as a calibrant) to determine transition pressures.

Main Results:

• The developed apparatus successfully generated pressures exceeding 220 kilobars.
• Precise pressure values for the semiconductor-to-metal transitions of ZnTe, ZnS, GaAs, and GaP were determined.
• The split-octahedron design was shown to be compatible with standard X-ray camera methods.

Conclusions:

• The split-octahedron apparatus is an effective tool for high-pressure X-ray diffraction studies.
• This method provides accurate measurements of critical transition pressures in semiconductors.
• The findings advance the understanding of electronic and structural phase transitions in materials under extreme conditions.