VASP not outputting band structure

[madhu_menon2]

Hi,
I am running VASP for DOS and band structure. It calculated DOS but fails to calculate the band structure. I get the following error in VASP.out. Any suggestions? Thanks.

POSCAR found : 3 types and 24 ions
scaLAPACK will be used

-----------------------------------------------------------------------------
| |
| W W AA RRRRR N N II N N GGGG !!! |
| W W A A R R NN N II NN N G G !!! |
| W W A A R R N N N II N N N G !!! |
| W WW W AAAAAA RRRRR N N N II N N N G GGG ! |
| WW WW A A R R N NN II N NN G G |
| W W A A R R N N II N N GGGG !!! |
| |
| For optimal performance we recommend to set |
| NCORE= 4 - approx SQRT( number of cores) |
| NCORE specifies how many cores store one orbital (NPAR=cpu/NCORE). |
| This setting can greatly improve the performance of VASP for DFT. |
| The default, NCORE=1 might be grossly inefficient |
| on modern multi-core architectures or massively parallel machines. |
| Do your own testing !!!! |
| Unfortunately you need to use the default for GW and RPA calculations. |
| (for HF NCORE is supported but not extensively tested yet) |
| |
-----------------------------------------------------------------------------


-----------------------------------------------------------------------------
| |
| ADVICE TO THIS USER RUNNING 'VASP/VAMP' (HEAR YOUR MASTER'S VOICE ...): |
| |
| You have a (more or less) 'large supercell' and for larger cells |
| it might be more efficient to use real space projection opertators |
| So try LREAL= Auto in the INCAR file. |
| Mind: For very accurate calculation you might also keep the |
| reciprocal projection scheme (i.e. LREAL=.FALSE.) |
| |
-----------------------------------------------------------------------------

LDA part: xc-table for Pade appr. of Perdew


VERY BAD NEWS! internal error in subroutine IBZKPT:
Reciprocal lattice and k-lattice belong to different class of lattices. Often results are still useful... 168000

[merzuk.kaltak]

Please upload INCAR, POTCAR, POSCAR, KPOINTS and OUTCAR (as a zip file).

[alex]

Hi madhu_menon2,

this indicates often that your reciprocal lattice has a different crystal class.

My guess: you have a rhombohedral or hexagonal system but you did _not_ shift your k-point mesh to the gamma point. E.g. my KPOINTS

Monk
0
Gamma
6 6 6

Cheers,

alex

[madhu_menon2]

Thank you!

[madhu_menon2]

Hi Alex,
I did as you suggested (shifting k-point mesh to the gamma point and using 666). The error now is:
ERROR: The band structure could not be written. Can't find data in EIGENVAL!
I also see a warning in VASP.out
WARNING: Sub-Space-Matrix is not hermitian in DAV 1
6.59593628981677

How can I fix this? Thanks.

[madhu_menon2]

Hi Merzuk Kaltak,
I am attaching the zipped files as you suggested. Please advice how to fix the error in computing DOS and band structure. Thanks. Regards.

[merzuk.kaltak]

You have uploaded you input files only, the output is still missing.
Also note, messages like

Code: Select all

VERY BAD NEWS! internal error in subroutine IBZKPT:
Reciprocal lattice and k-lattice belong to different class of lattices. Often results are still useful... 168000

are not errors and might go away by changing the default value of SYMPREC in the INCAR.

However, judging from your first post and the input files, it seems that you want to compute the band structure and relax the cell-structure (you have selected IBRION=2) all in one go.
We suggest to split this into to main steps consisting out of 3 individual steps:
1. Relaxing the structure (IBRION=2)
2.1 Use the CONTCAR of 1. to calculate the ground state
2.2 Compute the band structure using the CHGCAR and WAVECAR from 2.1 and setting (ICHARG=11)

There are also tutorials on our wiki that will help you performing these steps:
Relaxation
Computation of DOS
Band structure calculation after DOS calculation

[madhu_menon2]

This worked. Thanks!