[Pw_forum] problem in electronic structure of ZnO

[Arles V. Gil Rebaza]

Dear Muhammad Zafar:
In your structure, were optimized the lattice parameter and atomic
positions..??  ecutwfc = 25.0 was obtained after a convergence..?? and
finally, may be you need increase the k-points values (after a convergence).

Best


PhD stud. Arles V. Gil Rebaza
Institute of Physic of La Plata
La Plata - Argentine


2011/8/15 zafar rasheed <zafartariq2003 at yahoo.com>

> Dear All
>
> I plot ZnO electronic structure using this file given below
>
>
>
> &control
>
> Title = 'ZnO , hcp,a=3.2500,c=5.206 ,c/a=1.6103125',
>
> calculation ='scf'
>
> restart_mode='from_scratch',
>
> pseudo_dir = '/root/Pwscf/pseudo/',
>
> outdir ='/root/Pwscf/scratch/'
>
> prefix ='ZnO'
>
> tstress = .false.
>
> tprnfor = .false.
>
> /
>
> &system
>
> ibrav= 4,
>
> celldm(1) = 6.132075472,
>
> celldm(3) = 1.601846154,
>
> nat =4,
>
> ntyp =2,
>
> ecutwfc =25.0,
>
> ecutrho =300.0
>
> occupations ='smearing',
>
> smearing='methefessel_paxton',
>
> degauss = 0.05,
>
> /
>
> &electrons
>
> diagonalization='cg' ,
>
> conv_thr = 1.0e-8
>
> mixing_beta = 0.7
>
> /
>
> ATOMIC_SPECIES
>
> Zn 65.409 Zn.pz-van_ak.UPF
>
> O 15.9994 O.pz-van_ak.UPF
>
> ATOMIC_POSITIONS (crystal)
>
> Zn 0.333333333 0.666666667 0.0000000
>
> O 0.333333333 0.666666667 0.3817000
>
> Zn 0.666666667 0.333333333 0.5000000
>
> O 0.666666667 0.333333333 0.8817000
>
> K_POINTS (automatic)
>
> 4 4 4 0 0 0
>
>
>
>  This plot (after changing scf to nscf) is same as experimental and
> theoretical
>
>
>
>  BUT
>
>
>  when I make a cell of 8 atoms (1x1x2 supercell)
>
> input is as below
>
>
>
>  &control
>
> calculation ='scf'
>
> restart_mode='from_scratch',
>
> pseudo_dir = '/root/Pwscf/pseudo/',
>
> outdir ='/root/Pwscf/scratch/'
>
> prefix ='ZnO'
>
> tstress = .false.
>
> tprnfor = .true.
>
> /
>
> &system
>
> ibrav = 4,
>
> celldm(1) = 6.132075472,
>
> celldm(3) = 3.203692308, (due to increase in size along Z-direction C= 2*c
> )
>
> nat = 8,
>
> ntyp = 2,
>
> ecutwfc = 25.0,
>
> ecutrho = 300.0
>
> occupations ='smearing',
>
> smearing ='methefessel_paxton',
>
> degauss =0.02
>
> /
>
> &electrons
>
> diagonalization='cg' ,mixing_mode='plain',
>
> conv_thr = 1.0e-8
>
> mixing_beta = 0.7
>
> /
>
> ATOMIC_SPECIES
>
> Zn 65.38 Zn.pz-van_ak.UPF
>
> O 16.00 O.pz-van_ak.UPF
>
> ATOMIC_POSITIONS (crystal)
>
> Zn 0.333333333 0.666666667 0.000000000
>
> Zn 0.333333333 0.666666667 0.500000000
>
> Zn 0.666666667 0.333333333 0.250000000
>
> Zn 0.666666667 0.333333333 0.750000000
>
> O 0.333333333 0.666666667 0.190850000
>
> O 0.333333333 0.666666667 0.690850000
>
> O 0.666666667 0.333333333 0.440850000
>
> O 0.666666667 0.333333333 0.940850000
>
> K_POINTS (automatic)
>
> 4 4 4 0 0 0
>
>
>  After changing scf to bands the electronic structure is metallic (no band
> gap) and a I get different electronic structure . Now please guide me how I
> can get true electronic structure.
>
>
>  Thanking in Advance
>
>
> Muhammad Zafar
> PhD Scholar
> Department of Physics
> The Islamia University of Bahawalpur,Pakistan
> _______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://www.democritos.it/mailman/listinfo/pw_forum
>
>


-- 
###--------->   Arles V.   <---------###
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20110815/c24db579/attachment.html>