Disorder and demixing in bidisperse particle systems assembling bcc crystals

Area of Science:

• Materials Science
• Nanotechnology
• Physical Chemistry

Background:

• Colloidal and nanoparticle self-assembly is crucial for creating functional materials.
• The uniformity of nanoparticles significantly influences the success of self-assembly processes.

Purpose of the Study:

• To investigate the impact of bidispersity (two distinct particle sizes) on self-assembly.
• To determine the robustness of body-centered cubic (bcc) crystal formation in binary systems with varying particle size ratios.

Main Methods:

• Exploration of particle size dispersity, specifically bidispersity.
• Investigation of self-assembling bcc-type crystals using isotropic interaction potentials.
• Determination of the terminal size ratio for mixed binary bcc crystal formation.

Main Results:

• Two-well pair potentials demonstrate greater robustness in forming bcc crystals compared to one-well potentials, across a wider range of particle size ratios.
• A second attractive length scale in particle interactions stabilizes the second-nearest neighbor shell, enhancing self-assembly.
• Qualitative differences in ordering/disordering were observed: one-well potentials showed order breakdown before demixing, while two-well potentials allowed bcc formation down to low size ratios.

Conclusions:

• Utilizing two-well potentials in nanoparticle interactions improves self-assembly robustness against particle size variations.
• The findings suggest a pathway for designing more stable and ordered nanostructures through tailored inter-particle interactions.