[Pw_forum] Transmission from PWCOND

[Sclauzero Gabriele]

Dear Vladislav,

   I think there was an erroneous extra factor 2 in some PWcond versions between 5.0 and 5.0.2. I would stick to the latest stable version 5.1, recently released.

Best regards,


GS



> I calculate the spin-polarized transmission for a tunnel junction
> using the PWCOND code. The calculation is performed for each k-point
> in the irreducible part of the Brillouin Zone separately.
> At the end of each output file one sees the contributions to the
> transmission from different propagating states (an example is shown
> below for the 5.0.1 version of the code).
> 
> ************************************************************
> The input for PWCOND:
> 
>  &inputcond
>    outdir       = '/scratch/vborisov/tmp/test/',
>    prefixl      = 'lead',
>    prefixs      = 'scat',
>    tran_file    = 'T-k1.Ef'
>    ikind        = 1,
>    iofspin      = 1,
>    energy0      = 0.00d0,
>    denergy      = -0.01d0,
>    ewind        = 2.d0,
>    epsproj      = 1.d-7,
>    delgep       = 1.d-7,
>    cutplot      = 3.d0,
>    nz1          = 22,
>    bds          = 9.667070904
>  /
>    1
>    0.00347222  0.00694445   1
>    1
> 
> 
> A part of the output:
> 
> ---  E-Ef =    0.0000000  k =    0.0034722   0.0069444
> ---  ie =          1  ik =          1
>  Nchannels of the left tip =            1
>  Right moving states:
>    k1(2pi/a)   k2(2pi/a)   E-Ef (eV)
>   -0.3924556   0.0000000   0.0000000
>  Left moving states:
>    k1(2pi/a)   k2(2pi/a)   E-Ef (eV)
>    0.3924556   0.0000000   0.0000000
> 
>  to transmit
>  Band j to band i transmissions and reflections:
>     j         i     |T_ij|^2    |R_ij|^2
> 
>     1 -->     1     0.00014     0.99986
>    Total T_j, R_j =    0.00014  0.99986
> 
>           E-Ef(ev), T =    0.0000000   0.0001402
>  Eigenchannel decomposition:
> #    1  0.00000  0.00014
>                       1.00000
>    T_tot     0.00000      0.28041E-03
> 
> ************************************************************
> 
> From this output, one would conclude that the transmission for
> this k-point equals 0.1402E-03. However, after this result comes
> also the eigenchannel decomposition and the T_tot value, which
> is twice as large and equals 0.28041E-03. The same behavior is
> observed for every other k-point. However, this discrepancy
> does not appear for the CVS version of the code.
> 
> Where does this factor of 2 come from in the older version?
> Do the values of T_tot in these two versions always differ
> by the same factor of 2?
> 
> I would very much appreciate any assistance with this problem.
> 
> 
> With kind regards,
> Vladislav Borisov
> 
> Max Planck Institute of Microstructure Physics
> Weinberg 2, 06120, Halle (Saale), Germany
> Tel No: +49 345 5525448
> Fax No: +49 345 5525446
> Email: vborisov at mpi-halle.mpg.de
> 
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Dr. Gabriele Sclauzero
Materials Theory - ETHZ
ETH Zurich, HIT G 43.2
Wolfgang-Pauli-Str. 27
8093 Zürich, Switzerland

Phone +41 44 633 94 10
Fax +41 44 633 14 59
gabriele.sclauzero at mat.ethz.ch
www.theory.mat.ethz.ch