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Dear All,
I have calculated successfully GGA+U calculation for Bulk
material. However, I have met serious difficulties when trying to calculate
GGA+U+SO .
For non collinear calculation using all files from previous magnetic
collinear calculations and change INCAR file as written in vasp mannual.
As I am not a VASP expert my input settings might be wrong.
Below is the changes in the INCAR file.


############################################################################
ISTART = 1
ICHARG= 11 ! non selfconsistent run , read CHGCAR
MAGMOM =0 0 3.5 0 0 3.5 0 0 -3.0 0 0 -3.0 0 0 -3.0 0 0 -3.0 0 0 0.1 0
0 0.1 0 0 0.1 0 0 0.1 0 0 0.1 0 0 0.1 0 0 0.1 0 0 0.1

LNONCOLLINEAR = .TRUE.
NBANDS = 104 | 2* 52 no of bands for collinear run
ISYM = 0

LSORBIT = .TRUE.
LORBMOM = .TRUE.
VOSKHON = 1
GGA_COMPAT = .TRUE.

###########################################################################

But it gives the error "LAPACK: Routine ZPOTRF failed" and program stops
giving the following message:


POSCAR found : 3 types and 14 ions
LDA part: xc-table for Ceperly-Alder, standard interpolation

| Full k-point grid generated
| Inversion symmetry is not applied |
found WAVECAR, reading the header
number of k-points has changed, file: 28 present: 864
trying to continue reading WAVECAR, but it might fail
WARNING: stress and forces are not correct
POSCAR, INCAR and KPOINTS ok, starting setup
WARNING: wrap around errors must be expected
FFT: planning ... 1
reading WAVECAR
reading wavefunctions of collinear run, up
reading wavefunctions of collinear run, down
the WAVECAR file was read sucessfully
charge-density read from file: Fd-3m
magnetization density read from file 1
LAPACK: Routine ZPOTRF failed! 1

########################################################################

I found from the posted mails in forum that one used encountered same problem and overcomed it by removing WAVECAR file. I also used the same trick, but then also failed. If anyone can give me any kind of suggestion ,
it would be really great.

Thanks in Advance

With Best Regards,

Soumendu
soumendu@bose.res.in

I also ran into this problem, but I found a solution. The problem comes from doing previous calculations with a reduced k-point mesh produced by symmetry operations.

I imagine you generated the k-mesh automatically. The failed SOC run should have produced an IBZKPT file. Take this file, and rename it KPOINTS. Setting ISYM=0, re-do your collinear calculation using this new file to generate your kpoint mesh. The WAVECAR and CHGCAR files you produce should be compatible with SOC calculations. Just make sure you use the exact same k-point mesh and set NBANDS = 2*collinear-run value.