Accurate band gaps from exchange potentials designed from a cuspless hydrogen density-based exchange hole model

Area of Science:

• Condensed matter physics
• Materials science
• Computational chemistry

Background:

• Accurate prediction of material band gaps is crucial for electronic and photovoltaic applications.
• Explicit exchange-correlation (XC) potentials offer efficiency but require careful construction.
• The MBJ potential is a successful XC potential for band gap calculations.

Purpose of the Study:

• To develop and evaluate novel explicit XC potentials for improved band gap prediction.
• To investigate the performance of modified Becke-Roussel (BR) potentials within the MBJ framework.
• To assess the applicability of these new potentials for diverse material types, including semiconductors and topological insulators.

Main Methods:

• Construction of a BR-like potential using cuspless hydrogen density and its exchange hole.
• Application of a Laplacian-free exchange hole model within the MBJ framework.
• Calculation of band gaps for various material sets, including narrow, intermediate, and wide bandgap materials, and eighteen ternary chalcopyrite semiconductors.

Main Results:

• The new potentials provide band gaps closer to experimental values, especially when MBJ overestimates the gap.
• The modified potentials demonstrate improved accuracy for ternary semiconductors relevant to photovoltaics.
• The potentials successfully predict the band structure of three-dimensional topological insulators.

Conclusions:

• Modified explicit XC potentials offer a promising alternative for accurate band gap calculations.
• These potentials enhance the predictive power for materials with photovoltaic applications and topological properties.
• The study highlights the importance of tailored exchange hole models for improving electronic structure calculations.