[Pw_forum] Inconsistency between DOS and Band structure

Pietro Delugas pdelugas at sissa.it
Fri Sep 9 18:49:25 CEST 2016


Hi Habib

there were too many k-points so the program is not printing out the 
eigenvalues in the standard ouput, but if I understand correctly, the 
dos computed with dos.x is in agreement with the pdoses computed with 
projwfc.x, is it right ?

It's hard to understand what went wrong, I  would  check that the 
k-point mesh  used for the selfconsistent computation was well converged 
and that I have  been using  the  same charge density ( and that it is a 
correct one)    for  bands and  dos  non-scf calculations.

Just one more thing which, likely  has nothing to do with your problem: 
when you use norm-conserving pseudopotential there is no use in setting 
a value of ecutrho in the input.

greetings -pietro


On 09/09/2016 18:05, Ullah, Habib wrote:
>
> Dear Pietro,
>
> Thanks for your reply and guidance. Yes, first I did the NSCF 
> simulation, and after that the dos.x and Projwfc.x; kindly have a look 
> on the attached non-scf output file.
>
> Kind regards
>
> Habib
>
> *From:*pw_forum-bounces at pwscf.org [mailto:pw_forum-bounces at pwscf.org] 
> *On Behalf Of *Pietro Delugas
> *Sent:* 09 September 2016 16:43
> *To:* PWSCF Forum <pw_forum at pwscf.org>
> *Subject:* Re: [Pw_forum] Inconsistency between DOS and Band structure
>
> Hi Habib
>
> You should have a look to the eigenvalues you obtained in the  non 
> self consistent computation you made before doing the pdos.
>
> Have you tried to compute the dos using the dos.x program using those 
> same eigenvalues ?
>
> Also check, in the standard output of projwfc.x what are the 
> projections for the eigenfunctions close to the band edges
>
>
> Greetings - Pietro
>
> Il 09 set 2016 5:01 PM, "Ullah, Habib" <hu203 at exeter.ac.uk 
> <mailto:hu203 at exeter.ac.uk>> ha scritto:
>
>     Dear QE Users,
>
>     I am calculating the DOS/PDOS and Band Structure of BiVO4 but
>     getting different band gaps. i.e., in case of DOS/PDOS the band
>     gap is 2.1 eV while in the band structure simulations, it is 1.40
>     eV. I am using the same pseudopotentials for these simulations.
>     Any one knows, where I am doing the mistake??
>
>     Kind regards
>
>     Habib
>
>     The input/script for the PDOS is!
>
>     &PROJWFC
>
>         outdir = '/home/ISAD/hu203/Test/BiVO4/' ,
>
>         prefix = 'BiVO4'
>
>         degauss = 0.02,
>
>         filpdos = 'BiVO4.pdos' ,
>
>         Emin = -25.0,
>
>         Emax = 25.0,
>
>         DeltaE = 0.01,
>
>     /
>
>     While for the band structure simulations, the input is!
>
>     &CONTROL
>
>       calculation='bands',
>
>     outdir='/home/ISAD/hu203/Bismuth/BiVO4_Bulk/Optimized-BiVO4/',
>
>       prefix='BiVO4-bulk',
>
>     pseudo_dir='/home/ISAD/hu203/habib/espresso-5.0.3/pseudo/',
>
>       verbosity='high',
>
>       tstress=.false.,
>
>       tprnfor=.false.,
>
>     /
>
>     &SYSTEM
>
>       ibrav=6,
>
>       celldm(1)=9.7264200532d0, celldm(3)=2.2773654464d0,
>
>       nat=24,
>
>       ntyp=3,
>
>       ecutwfc=50.0d0,
>
>       ecutrho=500.0d0,
>
>       input_dft='LDA',
>
>       occupations='smearing',
>
>       smearing='Marzari-Vanderbilt',
>
>       degauss=0.002000d0,
>
>     /
>
>     &ELECTRONS
>
>       diagonalization='david',
>
>       conv_thr=1d-06,
>
>       mixing_mode='plain',
>
>       mixing_beta=0.700d0,
>
>     /
>
>     &IONS
>
>     ion_dynamics='bfgs'
>
>     /
>
>     &CELL
>
>     cell_dynamics='bfgs'
>
>     /
>
>     ATOMIC_SPECIES
>
>       Bi 208.980000d0 Bi.pz-hgh.UPF
>
>       O 15.999400d0 O.pz-hgh.UPF
>
>       V 50.941500d0 V.pz-n-nc.UPF
>
>     ATOMIC_POSITIONS {alat}
>
>       Bi      -0.000000471   0.249996017 1.423344718
>
>       Bi       0.000000471   0.750003983 0.854020728
>
>       Bi       0.500000213   0.749997379 0.284678980
>
>       Bi       0.499999787   0.250002621 1.992686467
>
>       V       -0.000003024   0.249994359 0.284670658
>
>       V        0.000003024   0.750005641 1.992694788
>
>       V        0.499995001   0.749991398 1.423364351
>
>       V        0.500004999   0.250008602 0.854001096
>
>       O        0.155441724   0.505701408 0.475790644
>
>      O        0.844558291   0.494298592 1.801574768
>
>       O        0.344551861   0.494281095 1.614473212
>
>       O        0.655448139   0.505718905 0.662892234
>
>       O        0.244301959   0.405442926 1.045129589
>
>       O        0.755698041   0.594557074 1.232235857
>
>       O        0.255708742   0.594561054 2.183807364
>
>       O        0.744291258   0.405438946 0.093558117
>
>       O        0.655440753   1.005707807 1.614459537
>
>       O        0.344559247  -0.005707807 0.662905910
>
>       O        0.844558823  -0.005710586 0.475801005
>
>       O        0.155441192   1.005710586 1.801564407
>
>       O        0.744296280   0.905441554 2.183811886
>
>       O        0.255703720   0.094558431 0.093553594
>
>       O        0.755708996   0.094565293 1.045123098
>
>       O        0.244291004   0.905434692 1.232242348
>
>     K_POINTS {crystal_b}
>
>     11
>
>        0.0000000000     0.0000000000 0.0000000000   50 !  G
>
>        0.0000000000     0.5000000000 0.0000000000   50 !  X
>
>        0.0000000000     0.5000000000 0.5000000000   50 !  R
>
>        0.0000000000     0.0000000000 0.5000000000   50 !  Z
>
>        0.0000000000     0.0000000000 0.0000000000   50 !  G
>
>        0.5000000000     0.5000000000 0.0000000000   50 !  M
>
>        0.5000000000     0.5000000000 0.5000000000   50 !  A
>
>        0.0000000000     0.0000000000 0.5000000000   50 !  Z
>
>        0.5000000000     0.0000000000 0.5000000000   50 !  R
>
>        0.5000000000     0.0000000000 0.0000000000   50 !  X
>
>        0.0000000000     0.0000000000 0.0000000000   50 !  G
>
>
>
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