Improving band gap prediction in density functional theory from molecules to solids

Area of Science:

• Computational Chemistry
• Materials Science
• Quantum Mechanics

Background:

• Density functional theory (DFT) methods often struggle with accurate band gap prediction.
• Predicting electronic band gaps is crucial for understanding and designing materials.

Purpose of the Study:

• To develop a novel nonempirical scaling correction method for DFT.
• To improve the accuracy of band gap predictions for finite systems.

Main Methods:

• Developed a nonempirical scaling correction method.
• Applied the correction to mainstream density functional approximations.
• Tested the method on systems ranging from atoms to solids.

Main Results:

• The scaling correction restores linear behavior of electronic energy at fractional electron numbers.
• Significant improvements in band gap prediction accuracy were observed across various DFT approximations.
• A scaled modified local density approximation showed consistent accuracy for all system sizes.

Conclusions:

• The developed scaling correction method offers a robust tool for accurate band gap prediction.
• The scaled modified local density approximation is effective for characterizing size-dependent energy gap effects in nanostructures.