[Pw_forum] Inconsistency between DOS and Band structure

Fri Sep 9 19:04:24 CEST 2016

Hi Pietro,

Yes, the band gap obtained from the dos.x is consistent with the projwfc.x. And the k-point mesh was well converged in the scf computation, which is further used (charge density) for the NSCF calculations.
Thanks for the correction of the ecutrho value.
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 17:49
To: PWSCF Forum <pw_forum at pwscf.org>
Subject: Re: [Pw_forum] Inconsistency between DOS and Band structure

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> [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><mailto: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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