Crystal Structures of CaB₃N₃ at High Pressures

Area of Science:

• Materials Science
• Solid-State Chemistry
• Computational Materials Science

Background:

• Calcium boron nitride (CaB3N3) is structurally analogous to graphite intercalated compound CaC6.
• Understanding the high-pressure behavior of novel ternary compounds is crucial for materials discovery.

Purpose of the Study:

• To investigate the structural stability and electronic properties of CaB3N3 under high pressure.
• To identify potential high-pressure phases and their characteristics.

Main Methods:

• Global structure searches were employed to explore possible stable structures.
• Phonon and electronic structure calculations were performed to assess stability and electronic properties.

Main Results:

• Two high-pressure phases of CaB3N3, with space groups R3c and Amm2, were identified as stable between 29-42 GPa and above 42 GPa, respectively.
• The R3c phase is a semiconductor with a 2.21 eV band gap, while the Amm2 phase is a semimetal.
• Both identified structures were confirmed to be dynamically stable at high pressures.

Conclusions:

• The study elucidates the high-pressure structural phase transitions of CaB3N3.
• The findings contribute to the fundamental understanding of the Ca-B-N ternary system and its potential electronic applications.