Run for alloy

[hpaudel]

Dear VASP users,

I am calculating band structure for Pb, Sn and Te alloy. I made a supercell by doubling the primitive lattice vectors. It has fcc (NaCl) structures. With primitive lattice vectors there are 2 basis vectors for fcc structure (one for Na and one for Cl). Once I have supercell it will have impurity included (in my case Sn doping) in supercell.

Following is my POSCAR file for alloy. I included all the atoms that lie within the supercell. There are 3 Sn atoms to get 20% doping that replaces Pb atoms (Pb_0.8Sn_0.2Te).

SYSTEM = PbSnTe
1.00000000000000
0.00000000 6.55000000 6.55000000
6.55000000 0.00000000 6.55700000
6.55000000 6.55000000 0.00000000
11 3 13
Cartesian
0.00000000 0.00000000 0.00000000 #Pb
6.55000000 0.00000000 0.00000000 #Pb
6.55000000 6.55000000 0.00000000 #Pb
0.00000000 6.55000000 0.00000000 #Pb
3.27500000 0.00000000 3.27500000 #Pb
6.55000000 3.27500000 3.27500000 #Pb
3.27500000 6.55000000 3.27500000 #Pb
6.55000000 0.00000000 6.55000000 #Pb
0.00000000 0.00000000 6.55000000 #Pb
6.55000000 6.55000000 6.55000000 #Pb
0.00000000 6.55000000 6.55000000 #Pb
3.27500000 3.27500000 0.00000000 #Sn
0.00000000 3.27500000 3.27500000 #Sn
3.27500000 3.27500000 6.55000000 #Sn
0.00000000 3.27500000 0.00000000 #Te
3.27500000 6.55000000 0.00000000 #Te
3.27500000 0.00000000 0.00000000 #Te
6.55000000 3.27500000 0.00000000 #Te
0.00000000 0.00000000 3.27500000 #Te
6.55000000 0.00000000 3.27500000 #Te
3.27500000 3.27500000 3.27500000 #Te
6.55000000 6.55000000 3.27500000 #Te
0.00000000 6.55000000 3.27500000 #Te
3.27500000 0.00000000 6.55000000 #Te
6.55000000 3.27500000 6.55000000 #Te
0.00000000 3.27500000 6.55000000 #Te
3.27500000 6.55000000 6.55000000

Following is the INCAR file.


SYSTEM = PbSnTe
ISTART = 0 # 0 start fr. scratch, no wavefunction WAVECAR need,
# 2 start from previous WAVECAR
ICHARG = 2 # 2 start fr. scratch,
# 1 read from CHGCAR,
# 0 Calculate from WAVE function
# 11 read charge density from CHGCAR
#and keep constant during the subsequent run
LREAL=.FALSE. # reciprocal space projection scheme .FALSE.
# automatic real space projection scheme AUTO?
ISPIN = 2 # non spin polarized calculations 1
# spin polarized calculations 2
LSORBIT = .TRUE. # Include spin-orbit intercation
#LORBIT = 11
#LORBMOM = 11
#MAGMOM = 2*1
LMAXMIX = 4
SAXIS = 0 0 1 # Direction of spin axis
EDIFF = 0.0001 # Convergency of ELECTRONIC iteration
EDIFFG = -0.01 # Convergency of IONIC iteration
# "-" mean the condition for FORCE
ENCUT = 250 # Energy cuttoff, need to test your value
LWAVE = .TRUE. # Save wavefunction WAVECAR or not
LCHARG = .TRUE. # Save CHGCAR charge density
NELM = 200 # Maximum number of electronic iteration
NSW = 0 # maximum number of ionic iteration
# 0 or 1 mean there is no relaxation (fix everything)

IALGO = 48
#NGX=24
#NGY=24
#NGZ=24

#GGA = PE # This is defult in case of PAW_PBE.

IBRION = -1 # -1 Ions won't move
# 2 Do relaxation, ions will move after every ionic iteration
#ISIF = 2 # stress, relaxation, volume change
POTIM = 0.10 # time step for ionic-motion
TEBEG = 0.0 # start temperature
TEEND = 0.0 # final temperature
ISMEAR = -5 # 0 gaussian smearing
# -5 tetrahedron method
SIGMA = 0.2 # Width of smearing
SYMPREC = 1e-7
ISYM = 2



Now my question is that I always get an error in VASP run. Error is the following:

POSCAR, INCAR and KPOINTS ok, starting setup
WARNING: wrap around errors must be expected
LAPACK: Routine ZPOTRF failed! 10
LAPACK: Routine ZPOTRF failed! 10

Could you please give me what would be the solution for this?

Thank you.

[Danny]

1) aren't you missing one Te atom?
2) check the compilation/installation of LAPACK, and linking to it in VASP

[hpaudel]

Danny,

There are 13 Te atoms in the POSCAR file and in total 27 atoms. Is my supercell is ok which I made multiplying by 2 to all lattice vectors for the unit cell?
I did not have this problem before when I had small system (eg. PbTe which has fcc structure as well). Calculation was ok. Could it be still problem with LAPACK?

Thank you.

[Danny]

if your cell is obtained by multiplying the lattice vectors by two the number of atoms in your cell should be an eight-fold (or if you did not multiply all lattice vectors at least a twofold, aka an even number)