Cause of DFT convergence instability in spin-polarized magnetite/water calculations

Ascertain the exact cause of the instability observed in spin-polarized density functional theory self-consistency calculations for the magnetite (Fe3O4)/water interface—manifesting as incorrect local magnetizations or incorrect forces despite energy convergence—so as to identify the underlying mechanism (e.g., multiple local minima in the magnetic electronic energy) responsible for these corrupted results.

Background

The authors encountered significant difficulties in performing DFT calculations for the magnetite/water interface, including cases where the electronic self-consistency converged in energy but produced incorrect local magnetic moments or forces. Such issues led to corrupted data that required extensive cleaning procedures and cross-validation with a committee of neural network potentials.

They hypothesize that the instability may arise from the complexity of the magnetic electronic energy landscape, where multiple local minima can trap the self-consistency loop, but they explicitly state that the exact cause remains unresolved.