Atomistic Corrective Scheme for Supercell Density Functional Theory Calculations of Charged Defects

Area of Science:

• Computational Materials Science
• Solid State Physics
• Quantum Chemistry

Background:

• Accurate calculation of charged defect formation energies is crucial for understanding material properties.
• Existing methods based on continuum electrostatics have limitations in describing complex systems.
• Supercell density-functional theory (DFT) calculations often require corrections for charged defects.

Purpose of the Study:

• To present and validate a novel atomistic method for correcting formation energies of charged defects.
• To apply the method to various material systems, including bulk, surfaces, and low-dimensional structures.
• To demonstrate the method's generality and compare its performance with existing techniques.

Main Methods:

• Development of an atomistic model using a polarizable force field to represent material dielectric properties.
• Separation of dielectric screening into ionic and electronic contributions.
• Implementation of the polarizable force field within molecular dynamics simulation software.

Main Results:

• The new method successfully corrects formation energies for charged defects in various systems.
• Validation against systems in vacuo and comparison with continuum electrostatics methods show good agreement.
• Successful application to charged S vacancies in bulk and layered MoS2 demonstrates broad applicability.

Conclusions:

• The presented atomistic method offers a robust and versatile approach for correcting charged defect formation energies.
• The method's ability to handle different material dimensions and its ease of implementation make it a valuable tool.
• This work advances the accuracy of DFT calculations for defect studies in materials science.