Deciphering chemical order/disorder and material properties at the single-atom level.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Computational Chemistry

Background:

• Real materials contain defects and chemical disorder, impacting properties.
• Current methods struggle to link 3D atomic structures of defects to material properties.
• First-principles calculations (like DFT) need precise atomic data beyond average models.

Purpose of the Study:

• To determine the 3D atomic coordinates and chemical species in an iron-platinum nanoparticle.
• To correlate crystal defects and chemical order/disorder with material properties at the single-atom level.
• To enable direct input of experimental atomic data into density functional theory (DFT) calculations.

Main Methods:

• High-precision 3D atomic coordinate determination for 6,569 iron and 16,627 platinum atoms.
• Identification of crystal defects (grain boundaries, anti-phase boundaries) and point defects (anti-site, swap defects).
• Correlation of atomic structure with material properties using DFT.

Main Results:

• Detailed 3D atomic structure and chemical composition of the nanoparticle revealed.
• Unprecedented 3D detail of various crystal defects and chemical disorder identified.
• Experimentally determined atomic coordinates used directly in DFT for accurate property prediction (magnetic moments, anisotropy).

Conclusions:

• Combining 3D atomic structure determination with DFT advances understanding of structure-property relationships.
• Precise experimental atomic data can directly enhance the predictive power of quantum mechanics calculations.
• This approach is crucial for designing and understanding materials with complex defect structures.