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

Abstract

Hubbard-corrected density-functional theory (DFT+U) is widely employed to predict the physical properties of correlated materials; however, reliable predictions can be hindered by the presence of metastable solutions in the DFT+U calculations. This issue stems from the orbital physics inherent in DFT+U. To address this, we propose a method to circumvent metastable states by applying a random orbital-dependent local perturbation to the localized orbitals. This perturbation lifts the orbital degeneracy within the corrective functional of DFT+U, ensuring that the system converges to a low-energy state. We validate this approach by comparing it with results obtained using an occupation matrix control scheme in several test cases, including PuO₂, UO₂, β-Pu₂O₃, and NiO.