[Pw_forum] problem witch wurtzite structure

[Stefano de Gironcoli]

default setting for atomic coordinates is "alat", tha is cartesian 
coordinates in unit of alat...
you probably want "crystal" setting.
visualize the structure by Xcrysden to see the difference

stefano

On 06/06/2012 03:00 PM, ramzi alaya wrote:
> Dear all,
>
> I've tried calculated the bandstructure for Wurtzite AlN but am running into problems. I started off with experimental values ( a=5.87 a.u. c/a=1.60 and u=0.379), I then kept
> a and u constant and altered c/a. I found an unrealistically small value c/a ( c=0.9). I then tried keeping c/a constant and altering a my scf calculations stopped converging. Perhaps I have a mistake in my input file?
> Thank you for your help and advice.
> This is the input file for the "scf" calculation
>
> &control
>      calculation='scf'
>      restart_mode='from_scratch',
>      tstress = .true.
>      tprnfor = .true.
>      prefix='810-28',
>      pseudo_dir = '/home/projet/pseudo/',
>      outdir='/home/projet/tp/'
>   /
>   &system
>      ibrav=  4, celldm(1) =8.12, celldm(3) =0.9, nat= 4, ntyp= 2,
>      ecutwfc =50.0, ecutrho = 600.0,
>   /
>   &electrons
>      diagonalization='david'
>      conv_thr = 1.0e-6
>      mixing_beta = 0.7
>   /
> ATOMIC_SPECIES
>   al  26.9815 al_pz.upf
>   n  14.0067 n_pz.upf
> ATOMIC_POSITIONS
>   al  0.333333333  0.666666667  0.000000000
>   al  0.666666667  0.333333333  0.500000000
>   n   0.333333333  0.666666667  0.379000000
>   n   0.666666667  0.333333333  0.879000000
> K_POINTS (automatic)
>   6 6 4 1 1 1
>
>
>
> ****************************************************************************************************************************************************************************
> Ramzi Alaya
> E-mail : ramzialaya at hotmail.fr
> Faculté des Sciences de Gabès, Cité Erriadh 6072 Gabès- Tunisie
> Unité de Recherche sur les Hétéro-Epitaxies et Applications
>
>   		 	   		
>
>
> _______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://www.democritos.it/mailman/listinfo/pw_forum

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20120606/6e47ddf8/attachment.html>