Direct insight into the structure-property relation of interfaces from constrained crystal structure prediction

Area of Science:

• Materials Science
• Computational Physics
• Solid State Chemistry

Background:

• Predicting the energetics and electronic properties of reconstructed interfaces in heterogeneous materials remains a significant challenge.
• Existing first-principles methods lack systematic approaches for consistent predictions.

Purpose of the Study:

• To develop an efficient and accurate computational scheme for predicting interface energetics and electronic properties.
• To address the limitations in understanding heterogeneous material interfaces.

Main Methods:

• Extended the minima-hopping method with constraints for 2D atomic relaxation and interface atomic density variations.
• Utilized a combination of density-functional theory (DFT) and density-functional tight-binding (DFTB) calculations for energy and force computations.
• Applied the method to analyze symmetric and asymmetric tilt boundaries in polycrystalline silicon.

Main Results:

• Identified a rich polymorphism in interface reconstructions for polycrystalline silicon tilt boundaries.
• Classified recurring bonding patterns at interfaces in increasing order of energy.
• Established a clear relationship between specific bonding patterns and electrically active grain boundary states.

Conclusions:

• The developed computational scheme provides an efficient and accurate approach for studying interface structures and properties.
• The findings offer insights into structure-property relationships at grain boundaries in silicon.
• This work paves the way for a deeper understanding of heterogeneous materials at the atomic level.