[Pw_forum] phosphorene monolayer

[Gautam Gaddemane]

thank you Dario. When I use VASP I get the exact same result as mentioned
in the reference you have atatched but with quantum espresso I get
significantly different result especially the band gap.
If you can have a look at the relax input file I have attached in the email
and let met know if I should add anything else ?


&CONTROL
  calculation='vc-relax',
  outdir='./',
  prefix='calc',
  pseudo_dir='./',
  verbosity='high',
/

&SYSTEM
  ibrav=0,
  celldm(1)= 8.276999830d0
  nat=4,
  ntyp=1,
  ecutwfc=60,
  ecutrho=360,
  input_dft='lda',
  occupations='smearing',
  smearing='mv',
  degauss=0.005d0,
/

&ELECTRONS
  conv_thr=1d-06,
  mixing_beta=0.7d0,
/
&IONS
  ion_dynamics='bfgs'
/

&CELL
  cell_dynamics='bfgs'
  cell_dofree='2Dshape'
/
ATOMIC_SPECIES
  P 30.973800d0 P.pw-mt_fhi.UPF

ATOMIC_POSITIONS {crystal}

 P  0.090000004         0.000000000         0.050195117
 P  0.909999967         0.000000000         0.949804902
 P  0.590000033         0.500000000         0.949804902
 P  0.409999996         0.500000000         0.050195117

K_POINTS {automatic}

  12 12 1 0 0 0

CELL_PARAMETERS {alat}

     1.0000000000000000    0.0000000000000000    0.0000000000000000
     0.0000000000000000    0.7511415530000000    0.0000000000000000
     0.0000000000000000    0.0000000000000000   4.68036529200000000

thank you
Gautam


GAUTAM GADDEMANE
DEPARTMENT OF MATERIALS SCIENCE AND ENGINEERING
UNIVERSITY OF TEXAS AT DALLAS

On Thu, Oct 5, 2017 at 3:54 PM, dario rocca <roccad at gmail.com> wrote:

> Dear Gautam,
> The values you get are not completely impossible.
> Try with PBE, since there are for sure a couple of calculations in the
> literature to compare with.
> For example
> https://journals.aps.org/prb/abstract/10.1103/PhysRevB.90.085402
> Best,
> Dario
>
> On Thu, Oct 5, 2017 at 10:31 PM, Gautam Gaddemane <gautamg88 at gmail.com>
> wrote:
>
>> 4.45 A and 3.26 A and a band gap of 0.67eV.
>>
>> GAUTAM GADDEMANE
>> DEPARTMENT OF MATERIALS SCIENCE AND ENGINEERING
>> UNIVERSITY OF TEXAS AT DALLAS
>>
>> On Thu, Oct 5, 2017 at 3:28 PM, Matthieu Fortin-Deschênes <
>> matthieu.fortin-deschenes at polymtl.ca> wrote:
>>
>>> What values of lattice parameters and band gap did you get? With LDA
>>> you expect some differences compared to experimental values.
>>>
>>> Matthieu
>>>
>>> Gautam Gaddemane <gautamg88 at gmail.com> a écrit :
>>>
>>> > Dear All,
>>> >
>>> > I am trying to calculate the bands tructure for monolayer phosphorene
>>> and I
>>> > am just a week old in using quantum espresso.
>>> >> From the bulk unit cell I prepared an input file to relax the
>>> structure but
>>> > I was not able to get a good lattice constant nor a good band gap. It
>>> would
>>> > be very helpful if someone would guide me in this procedure.
>>> > I have attahced the file I used to relax in this email
>>> >
>>> >
>>> > &CONTROL
>>> >   calculation='vc-relax',
>>> >   outdir='./',
>>> >   prefix='calc',
>>> >   pseudo_dir='./',
>>> >   verbosity='high',
>>> > /
>>> >
>>> > &SYSTEM
>>> >   ibrav=0,
>>> >   celldm(1)= 8.276999830d0
>>> >   nat=4,
>>> >   ntyp=1,
>>> >   ecutwfc=60,
>>> >   ecutrho=360,
>>> >   input_dft='lda',
>>> >   occupations='smearing',
>>> >   smearing='mv',
>>> >   degauss=0.005d0,
>>> > /
>>> >
>>> > &ELECTRONS
>>> >   conv_thr=1d-06,
>>> >   mixing_beta=0.7d0,
>>> > /
>>> > &IONS
>>> >   ion_dynamics='bfgs'
>>> > /
>>> >
>>> > &CELL
>>> >   cell_dynamics='bfgs'
>>> >   cell_dofree='2Dshape'
>>> > /
>>> > ATOMIC_SPECIES
>>> >   P 30.973800d0 P.pw-mt_fhi.UPF
>>> >
>>> > ATOMIC_POSITIONS {crystal}
>>> >
>>> >  P  0.090000004         0.000000000         0.050195117
>>> >  P  0.909999967         0.000000000         0.949804902
>>> >  P  0.590000033         0.500000000         0.949804902
>>> >  P  0.409999996         0.500000000         0.050195117
>>> >
>>> > K_POINTS {automatic}
>>> >
>>> >   12 12 1 0 0 0
>>> >
>>> > CELL_PARAMETERS {alat}
>>> >
>>> >      1.0000000000000000    0.0000000000000000    0.0000000000000000
>>> >      0.0000000000000000    0.7511415530000000    0.0000000000000000
>>> >      0.0000000000000000    0.0000000000000000   4.68036529200000000
>>> >
>>> >
>>> > thank you
>>> > Gautam
>>> >
>>> > GAUTAM GADDEMANE
>>> > DEPARTMENT OF MATERIALS SCIENCE AND ENGINEERING
>>> > UNIVERSITY OF TEXAS AT DALLAS
>>>
>>>
>>>
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