Crystalline structures of particles interacting through the harmonic-repulsive pair potential

Area of Science:

• Condensed Matter Physics
• Materials Science
• Computational Physics

Background:

• Understanding particle interactions and resulting structures is crucial in condensed matter physics.
• Previous studies on harmonic-repulsive potentials did not predict the complex crystallizations observed.

Purpose of the Study:

• To investigate the behavior of identical particles under a harmonic-repulsive pair potential using molecular dynamics simulations.
• To identify and characterize novel crystalline structures formed at different densities and temperatures.

Main Methods:

• Three-dimensional molecular dynamics simulations were employed.
• The system consisted of identical particles interacting via a harmonic-repulsive pair potential.
• Simulations were conducted at various densities and decreasing temperatures.

Main Results:

• Crystallization into previously unobserved structures, including Ia3¯d (space group #230) and monoclinic C2/c (space group #15), was observed.
• The C2/c structure exhibited particles with different energies at distinct Wyckoff sites, resembling columnar quasicrystals.
• At certain densities, stable liquids resistant to crystallization, or no crystallization at all, were noted.
• Distorted beta-tin (βSn) diamond structures and a possible R3¯c hexagonal lattice were also observed.

Conclusions:

• The harmonic-repulsive pair potential can lead to the formation of complex and unanticipated crystal structures.
• The observed structures, such as Ia3¯d and C2/c, represent new findings in single-component systems.
• Particle behavior is highly sensitive to density, leading to diverse outcomes including stable liquids and novel crystalline phases.