The spin-contributions are calculated separately (T_j) and at the end all contributions are summed up and are weighted with their corresponding Brillouin-zone weight (wkpt, trans_tot) in do_cond.f90 -> T_tot. So I guess, it is either something wrong with the BZ-weighting (see summary_tran.f90 and do_cond.f90) or with the summation over iofspin (transmit.f90). You used nspin=2 in scf-calc and now separate the transmission by spin-channel, so I guess it's the latter. You should do a check for a simple (T_tot=2) non-metallic metal (eg. copper) and ferromagnetic metal (bcc iron) with both nspin=1&2.
You said the results of the 5.01 version and the CVS version differ. Which CVS/SVN Revision are you using? ------------------------------------------------------------- Nicki Frank Hinsche, Dr. rer. nat. Institute of physics - Theoretical physics, Martin-Luther-University Halle-Wittenberg, Von-Seckendorff-Platz 1, Room 1.07 D-06120 Halle/Saale, Germany Tel.: ++49 345 5525460 ------------------------------------------------------------- Am 12.06.2014 um 12:00 schrieb pw_forum-request at pwscf.org: > Date: Thu, 12 Jun 2014 08:38:31 +0200 > From: Vladislav Borisov <vborisov at mpi-halle.mpg.de> > Subject: [Pw_forum] Transmission from PWCOND > To: pw_forum at pwscf.org > Message-ID: <e99409ee66e329da56c59effeb2a7df3 at mpi-halle.mpg.de> > Content-Type: text/plain; charset=UTF-8; format=flowed > > Dear all, > > 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 -------------- next part -------------- An HTML attachment was scrubbed... URL: http://pwscf.org/pipermail/pw_forum/attachments/20140615/60340eb3/attachment.html
