[Pw_forum] Default value of nbnd for GaAs

[Mohammad Abu Raihan Miah]

Hi Krishnendu,

Thank you very much.

On Mon, Aug 1, 2016 at 10:29 AM, Krishnendu Ghosh <krish.besu at gmail.com>
wrote:

> You included semicore d states from Ga. That's giving 5 orbitals.
> On Aug 1, 2016 1:24 PM, "Mohammad Abu Raihan Miah" <mraihanm at eng.ucsd.edu>
> wrote:
>
>> Hi all,
>>
>> I am currently doing simulation to calculate the band structure of GaAs.
>> I use the basic primitive cell to simulate.
>>
>> In order to calculate the band structure I need to specify the number of
>> bands, nbnd parameter. Now as far as I understand, For GaAs there are 4
>> valence electrons per atom. So for a 2 atom primitive cell, the default
>> value of nbnd should be 4. But instead I get the default value of nbnd as 9
>> (I checked the value from output file as for each k, 9 eigen energy value
>> is calculated)
>>
>> My input file as follows:
>>
>>
>> &CONTROL
>>   calculation='scf',
>>   outdir='out_bulk',
>>   prefix='GaAs_2',
>>   pseudo_dir='.',
>>   verbosity='low',
>>   tstress=.false.,
>>   tprnfor=.false.,
>> /
>>
>> &SYSTEM
>>   ibrav=2,
>>   celldm(1)=10.6839445905d0,
>>   nat=2,
>>   ntyp=2,
>>   ecutwfc=50.0d0,
>>   ecutrho=400.0d0,
>>   input_dft='PBE',
>> /
>>
>> &ELECTRONS
>>   diagonalization='david',
>>   conv_thr=1d-06,
>>   mixing_mode='plain',
>>   mixing_beta=0.700d0,
>> /
>>
>> ATOMIC_SPECIES
>>   As 74.921600d0 As.pbe-n-rrkjus_psl.0.2.UPF
>>   Ga 69.723000d0 Ga.pbe-dn-rrkjus_psl.0.2.UPF
>>
>> ATOMIC_POSITIONS {alat}
>>   Ga   0.0000000000d0   0.0000000000d0   0.0000000000d0
>>   As   0.2500000000d0   0.2500000000d0   0.2500000000d0
>>
>> K_POINTS {automatic}
>>   8 8 8 0 0 0
>>
>>
>> Could anyone please explain that to me?
>>
>> Thank you very much.
>>
>> Best,
>> --
>> Mohammad Abu Raihan Miah
>> PhD Student
>> Department of Electrical and Computer Engineering (ECE)
>> <http://www.ece.ucsd.edu/>
>> University of California, San Diego <http://www.ucsd.edu/>
>>
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>
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-- 
Mohammad Abu Raihan Miah
PhD Student
Department of Electrical and Computer Engineering (ECE)
<http://www.ece.ucsd.edu/>
University of California, San Diego <http://www.ucsd.edu/>
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