Ordered binary crystal phases of Lennard-Jones mixtures

Area of Science:

• Computational materials science
• Condensed matter physics
• Chemical physics

Background:

• Understanding crystal structures and their stability is crucial for materials design.
• Lennard-Jones interactions provide a fundamental model for interatomic forces in many systems.
• Exploring the phase space of binary compounds can uncover new material properties.

Purpose of the Study:

• To calculate lattice energies for numerous crystal structures of ordered binary compounds at zero temperature.
• To identify the lowest energy crystal structures across a defined range of cross-species interaction parameters.
• To investigate the prevalence and stability of metastable crystal phases in binary systems.

Main Methods:

• Utilized Lennard-Jones potential to model interatomic interactions.
• Calculated lattice energies for a wide array of binary compound crystal structures.
• Systematically varied cross-species interaction parameters (sigmaAB, epsilonAB) within specified ranges.
• Included parameters relevant to binary glass-forming alloys.

Main Results:

• Identified known large unit cell structures (e.g., Ni3P, PuBr3) among the lowest energy configurations.
• Discovered novel low-energy crystal structures based on close-packed lattices, not previously observed experimentally.
• Examined the stability and occurrence of metastable crystal phases at compositions AB, A2B, and A3B.

Conclusions:

• The study expands the understanding of possible crystal structures for binary compounds.
• Novel, energetically favorable structures may serve as targets for future materials synthesis.
• Metastable phases play a significant role in the structural landscape of binary systems.