[Pw_forum] wrong nrztot

[Alexander]

Dear Sagar.
You can describe the fcc structure with tetragonal unit cell: 
a1=(a/2,-a/2,0)
a2=(a/2,a/2,0)
a3=(0,0,a)  
having two atoms at 0 and at 0.5*(a1+a2+a3).
Of course, you can use fcc as the leads but as it is implemented in pwcond
now your unit cell should be monoclinic (tetragonal is a particular case of 
monoclinic), i.e. such that a3 is perpendicular to both a1 and a2 and the 
direction of transport is a3. The one-dimensional complex bands are 
calculated at fixed (k1,k2) along the k3 direction which will coincide with 
a3. In the setup above with k1=k2=0 they will be complex bands in [001] 
direction. 
Anyway, [100] (what you want to calculate) and [001] (what is presented in the 
example 12) are equivalent directions in fcc.

Best regards,
Alexander
  
On Thursday 24 April 2008 08:21, ambavale sagar wrote:
> Dear Smogunov sir,
> Sorry but i can'at understand that why only tetragonal must be used as
> electrode bulk geometry? can't we use FCC?
> and how to define this(fcc) geometry using tetragonal unit cell with only
> two atoms?
>
> sagar
>
> %%%%%%%%%%%%%%%%%%%%%%%%%%
> Dear Sagar.
> This is because you should use the tetragonal
> unit cell with two atoms per cell like in the example 12.
> Regards,
> Alexander
>
> On Tuesday 22 April 2008 11:24, ambavale sagar wrote:
> > sorry, i forgot to attach  scf file  and  my  signature. so resending the
> > entire mail. i am using espresso 4.0cvs2 for calculating complex band
> > structure of al bulk in 100 direction( for 001 it is given in example
> > 12). this gives me following errror:
> >
> >  from in init_cond : error #   1626817
> >      wrong nrztot
> >
> > %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
> >%% %%%
> >
> >      stopping ...
> >
> > the input file for complex band is :
> >
> > &inputcond
> >     outdir='/db/sagar/tmp/'
> >     prefixl='al_bulk'
> >     band_file ='bands.albulk'
> >     ikind=0
> >     energy0=10.d0
> >     denergy=-0.4d0
> >     ewind=1.d0
> >     epsproj=1.d-3
> >     delgep = 1.d-12
> >     cutplot = 3.d0
> >  /
> >     1
> >     0.0 0.0 1.0
> >     60
> >
> > while the file for scf calculation is:
> >
> >  &control
> >     calculation='scf'
> >     restart_mode='from_scratch',
> >     pseudo_dir = '/db/espresso4.0cvs2/pseudo/',
> >     outdir='/db/sagar/tmp/',
> >     prefix='al_bulk'
> >     tprnfor = .true.
> >     tstress = .true.
> >  /
> >  &system
> >     ibrav=  2, celldm(1) =7.50, nat=  1, ntyp= 1, ecutwfc =15.0,
> >     occupations='smearing', smearing='marzari-vanderbilt', degauss=0.05
> >  /
> >  &electrons
> >     diagonalization='david'
> >     mixing_beta = 0.7
> >  /
> > ATOMIC_SPECIES
> >  Al  26.98 Al.vbc.UPF
> > ATOMIC_POSITIONS
> >  Al 0.00 0.00 0.00
> > K_POINTS (automatic)
> > 2 2 2 1 1 1
> >
> >
> > Sagar Ambavale
> > PhD student
> > The M.S.University of Baroda
> > Inida
>
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