Circumventing the Metastable States within DFT+<i>U</i> through Random Orbital-Dependent Local Perturbation
Ruizhi Qiu
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 PuO 2, UO 2, β-Pu 2 O 3, and NiO.