Circumventing the Metastable States within DFT+U through Random Orbital-Dependent Local Perturbation.

Area of Science:

• Computational materials science
• Condensed matter physics
• Quantum chemistry

Background:

• Density-functional theory (DFT) with a Hubbard correction (DFT+U) is crucial for predicting correlated material properties.
• Metastable solutions in DFT+U calculations can compromise the accuracy of these predictions.
• Orbital physics inherent in DFT+U contributes to the problem of metastable states.

Purpose of the Study:

• To propose and validate a novel method to overcome the challenge of metastable states in DFT+U calculations.
• To ensure accurate convergence to the true low-energy state for correlated materials.
• To improve the reliability of physical property predictions using DFT+U.

Main Methods:

• Application of a random, orbital-dependent local perturbation to localized orbitals.
• Perturbation designed to lift orbital degeneracy within the DFT+U corrective functional.
• Comparison of the proposed method against an occupation matrix control scheme.

Main Results:

• The proposed perturbation method effectively circumvents metastable states in DFT+U.
• The approach successfully guides the system towards a low-energy state.
• Validation performed on challenging test cases including PuO2, UO2, β-Pu2O3, and NiO.

Conclusions:

• The developed method offers a robust solution to the metastable state problem in DFT+U.
• This technique enhances the predictive power of DFT+U for correlated materials.
• The findings are significant for computational materials science and condensed matter physics research.