[Pw_forum] Transport with pw_cond copper

[Alexander Smogunov]

Dear Nicki, John

On Thursday 15 January 2009 17:46, J. D. Burton wrote:
> Nicki,
>
> PWCOND only works with tetragonal cells: either ibrav = 6 or use ibrav = 0
> with tetragonal CELL_PARAMETERS in your scf calculation. Notice all the
> calculations in example12 use ibrav = 6. Why do you want simple cubic Cu
> anyway? Cu is fcc, but you can’t use ibrav = 2 for PWCOND. You can set up
> your scf calculation like this:

Some time ago there was a discussion on the systems where PWCOND works,
It works not only for tetragonal unit cells but for general MONOCLINIC systems
where the transport direction (the z axis) is perpendicular to the xy plane. 
This is the only restriction on the geometry. It is right that some check on 
the allowed geometry would be useful to add before the code starts running...
   
>
> ibrav = 0
> celldm(1) = cubic lattice parameter for Cu in a.u.
>
> ATOMIC_POSITONS (crystal)
> Cu  0.0 0.0 0.0
> Cu  0.5 0.5 0.5
>
> CELL_PARAMETERS
> sqrt(2)/2 0.00      0.00
> 0.00      sqrt(2)/2 0.00
> 0.00      0.00      1.00
>

I think that should work. But you can use a simple tetragonal unit cell
with also 2 atoms/cell as it is shown in the example12 for bulk Al and Ni.
 
Best regards,
Alexander


> Anything useful that you might want to calculate (i.e. a junction) will be
> have to be at least tetragonal anyway. (Although I don't think even
> orthorhombic cells are implemented yet.)
>
> Cheers,
> J. D.
>
> ************************************
> J. D. Burton, Ph.D.
> jlz101 at unlserve.unl.edu
> University of Nebraska Lincoln
> Physics and Astronomy
> Office Ph. (402) 472 2499
> Mobile Ph. (402) 419 9918
> 213C Ferguson Hall
> ************************************
> "The job of a scientist is to generate wrong ideas as fast as possible."
> -- Murray Gell-Mann
>
> From: pw_forum-bounces at pwscf.org [mailto:pw_forum-bounces at pwscf.org] On
> Behalf Of Nicki F. Hinsche
> Sent: Tuesday, January 13, 2009 8:10 AM
> To: pw_forum at pwscf.org
> Subject: [Pw_forum] Transport with pw_cond copper
>
> Hi, I want to make some test calculations of transport through 'bulk'
> copper. Left and right lead shall be equal and the scattering region should
> be the same material as the lead itself. My problem is, that I cant get any
> results and I can't recognize any mistakes in my input cards -> my
> inputcards are:
>
> # self-consistent calculation for Cu bulk
>
>  &control
>     calculation='scf'
>     restart_mode='from_scratch',
>     pseudo_dir = '$PSEUDO_DIR/',
>     outdir='$TMP_DIR/'
>     prefix='cu'
>  /
>  &system
>     ibrav = 1
>     celldm(1) = 6.719
>     nat= 1,
>     ntyp= 1,
>     ecutwfc = 40.0,
>     occupations='smearing',
>     smearing='methfessel-paxton',
>     degauss=0.01
>  /
>  &electrons
>     conv_thr = 1.0e-12
>     mixing_beta = 0.5
>  /
> ATOMIC_SPECIES
>  Cu 63.55 Cu.pz-d-rrkjus.UPF
> ATOMIC_POSITIONS
>  Cu 0.0 0.0 0.0
> K_POINTS (automatic)
>  16 16 16 0 0 0
>
>
> # complex bands of Copper along the 001 direction K_perp=0
>
> cat > cu.cond.in << EOF
>  &inputcond
>     oudir='$TMP_DIR/'
>     prefixl='cu'
>     band_file ='bands.cu'
>     ikind=0
>     energy0=10.d0
>     denergy=-0.1d0
>     ewind=1.d0
>     epsproj=1.d-3
>     delgep = 1.d-12
>     cutplot = 2.d0
>  /
>     1
>     0.0 0.0 1.0
>     100
>
>
> # transmission calculation for the perfect copper contact
>
> cat > cutrans.cond.in << EOF
>  &inputcond
>     outdir='$TMP_DIR/',
>     prefixl='cu',
>     prefixs='cu',
>     tran_file='trans.cu',
>     ikind=1,
>     energy0=2.95d0,
>     denergy=-0.1d0,
>     ewind=1.d0,
>     epsproj=1.d-3,
>     nz1 = 1
>  /
>    1
>     0.0  0.0  1.0
>     100
>
>   
> I get the error message:
>
>      task #         1
>      from in init_cond : error # 172992232
>      wrong nrztot
>
>
> I would be thankful for every hint that you might give me...
>
>
>
>
> -------------------------------------------------------
> Nicki F. Hinsche
> Martin-Luther-Universitдt Halle-Wittenberg
> Naturwissenschaftliche Fakultдt II - Chemie und Physik
> Institut fьr Physik, Theoretische Physik
> D-06099 Halle (Saale)
> Telefon : +49-345/55-25460
> Forschungszentrum Dresden-Rossendorf
> Institut fьr Ionenstrahlphysik und Materialforschung
> Postfach 51 01 19
> D-01314 Dresden, Germany
> E-Mail : n.hinsche at fzd.de
>
>
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