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 <[email protected]> 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 <[email protected]>
> 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 <
>> [email protected]> 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 <[email protected]> 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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