Dear All, When I do the calculation of the electronic structure of slab Palladium under the external electric field, convergence problems appear. The typical problem is that the estimated scf accuracy value drop down down and bounce back. It seems that the calculation does not know where the system would go for minimizing the total energy. The electric field that I applied is saw-tooth like one. I tried many things like increasing the mixing_ndim, decreasing the mixing_betta to 0.1, adding empty bands changing the mixing mode and even increase the degauss. But, none of them would work for the scf accuracy oscillating problem. Below is the input file. Any suggestion is highly appreciated.
&control calculation='scf' restart_mode='from_scratch', pseudo_dir = '$PSEUDO_DIR/', outdir='$TMP_DIR/' prefix='Pd' tefield = .true. dipfield = .true. nstep = 300 / &system ibrav = 6 celldm(1) = 7.3331 nspin = 2 celldm(3) = 4.5 edir = 3 emaxpos=0.72 eopreg=0.28 eamp = -0.001944 starting_magnetization=0.05 ntyp = 1 nat= 14 ecutwfc = 25.0, ecutrho = 500.0, occupations='smearing', degauss=0.2 nbnd=160 / &electrons conv_thr = 1.0e-4 mixing_mode='local-TF' mixing_beta = 0.05 mixing_ndim = 12 / ATOMIC_SPECIES Pd 100 Pd.pz-nd-rrkjus.UPF ATOMIC_POSITIONS Pd 0.500000000 0.000000000 -1.496126804 Pd 0.000000000 0.500000000 -1.496126804 Pd 0.000000000 0.000000000 -1.002542052 Pd 0.500000000 0.500000000 -1.002542051 Pd 0.500000000 0.000000000 -0.501470158 Pd 0.000000000 0.500000000 -0.501470158 Pd 0.000000000 0.000000000 0.000000000 Pd 0.500000000 0.500000000 0.000000000 Pd 0.500000000 0.000000000 0.501470158 Pd 0.000000000 0.500000000 0.501470158 Pd 0.000000000 0.000000000 1.002542052 Pd 0.500000000 0.500000000 1.002542051 Pd 0.500000000 0.000000000 1.496126804 Pd 0.000000000 0.500000000 1.496126804 K_POINTS (automatic) 8 8 1 0 0 0 -- University of Nebraska at Lincoln