EDIFF
EDIFF = [real]
Default: EDIFF =
Description: EDIFF specifies the global break condition for the electronic SC-loop. EDIFF is specified in units of eV.
The relaxation of the electronic degrees of freedom will be stopped if the total (free) energy change and the band structure energy change ('change of eigenvalues') between two steps are both smaller than EDIFF (in eV). For EDIFF=0, strictly NELM electronic SC-steps will be performed.
Mind: In most cases the convergence speed is exponential, so often the cost for the few additional iterations is small. For high precision calculations, we recommend to decrease EDIFF to 1E-6. For finite difference calculations (e.g. phonons), even EDIFF = 1E-7 might be required in order to obtain very accurate results.