An atomic scale study of two-dimensional quasicrystal nucleation controlled by multiple length scale interactions

Area of Science:

• Materials Science
• Crystallography
• Condensed Matter Physics

Background:

• Quasicrystal structures, discovered decades ago, possess unique atomic arrangements that remain incompletely understood.
• The nucleation and formation mechanisms of quasicrystals with various symmetries (decagonal, dodecagonal, heptagonal, octagonal) present significant scientific challenges.

Purpose of the Study:

• To investigate the nucleation process of different quasicrystal structures.
• To elucidate the role of coupled length scales in controlling quasicrystal formation.
• To propose a geometric model explaining the cooperation of length scales during nucleation.

Main Methods:

• Utilized a dynamic phase-field crystal model for simulations.
• Analyzed the local rearrangement of length scales during nucleation.
• Developed a geometric model to describe the cooperation of length scales.

Main Results:

• Observed quasicrystal nucleation proceeds via local rearrangement of length scales.
• Identified the generation, merging, and stacking of 3-atom building blocks as key processes.
• Proposed a geometric model detailing the cooperation of length scales in structural transformation.

Conclusions:

• The cooperation and balance between multiple length scales are crucial for quasicrystal formation.
• This work clarifies the microscopic mechanisms governing quasicrystal nucleation.
• Findings contribute to understanding the common formation rules for both periodic crystals and quasicrystals.