Low pressure metastable single-bonded solid nitrogen phases

Area of Science:

• Materials Science
• Theoretical Chemistry
• Condensed Matter Physics

Background:

• High energy density materials are crucial for advanced applications.
• Nitrogen allotropes are promising candidates due to high nitrogen content.
• Previous studies focused on molecular nitrogen phases under pressure.

Purpose of the Study:

• Investigate the formation of single-bonded solid atomic nitrogen phases.
• Determine the stability and properties of these new phases.
• Compare novel atomic nitrogen structures with existing dynamically stable phases.

Main Methods:

• Density Functional Theory (DFT) calculations.
• Simulations of adiabatic compression of nitrogen structures.
• Analysis of crystal lattice symmetry and dynamic stability.

Main Results:

• Nitrogen clusters N8(C2v)-B transform into a dynamically stable P21 atomic phase under compression.
• The epsilon-N2 molecular phase converts to a stable R3c atomic phase above 30 GPa.
• Both P21 and R3c phases feature single-bonded atoms, storing significant energy (≈1.4 eV/atom).

Conclusions:

• New single-bonded solid atomic nitrogen phases (P21 and R3c) are predicted.
• These phases exhibit dynamic stability and high energy storage capacity.
• The findings contribute to the understanding of nitrogen allotropes for energy applications.