[DFTB-Plus-User] About DFTB+NEGF calculation

[yh46]

Hello dear friend,
I am trying to use DFTB+NEGF, version r4729, to calculate transmission  
of bulk gold Au 100 direction.
I first did a non-scc calculation, with this input file:
############################################
Geometry = GenFormat {
<<< 'Au_100.gen'
}

Transport {
     Device {
       AtomRange = 1 12
       FirstLayerAtoms =  1 7
     }
     Contact {
       Id = "source"
       AtomRange = 13   24
       FermiLevel [eV] = -0.2745
       potential [eV] = 0.0
     }
     Contact {
Geometry = GenFormat {
<<< 'Au_100.gen'
}

Transport {
     Device {
       AtomRange = 1 12
       FirstLayerAtoms =  1 7
     }
     Contact {
       Id = "source"
       AtomRange = 13   24
       FermiLevel [eV] = -0.2745
       potential [eV] = 0.0
     }
     Contact {
       Id = "drain"
       AtomRange = 25   36
       FermiLevel [eV] = -0.2745
       potential [eV] = 0.0
     }
}

Hamiltonian = DFTB {
   SCC = No
   OrbitalResolvedSCC = Yes
   MaxAngularMomentum = {
     Au = "d"
   }

   SlaterKosterFiles = Type2FileNames {
     Prefix = "./"
     Separator = "-"
     Suffix = ".skf"
   }
    KpointsAndWeights = SupercellFolding{
     1 0 0
     0 2 0
     0 0 2
     0.0 0.0 0.0
   }

   Eigensolver = TransportOnly{}

}

Analysis = {
TunnelingAndDos {
   Verbosity = 101
   EnergyRange [eV] = -6.5  3.0
   EnergyStep [eV] = 1
   Region = {
     Atoms = 1:36
   }
  }
}
#############################################
and geometry:
########################################
   36  S
  Au
1  1  21.689400000   0.000000000   0.000000000
2  1  23.496850000   1.278060152   1.278060152
3  1  25.304300000   0.000000000   0.000000000
4  1  27.111750000   1.278060152   1.278060152
5  1  28.919200000   0.000000000   0.000000000
6  1  30.726650000   1.278060152   1.278060152
7  1  32.534100000   0.000000000   0.000000000
8  1  34.341550000   1.278060152   1.278060152
9  1  36.149000000   0.000000000   0.000000000
10  1  37.956450000   1.278060152   1.278060152
11  1  39.763900000   0.000000000   0.000000000
12  1  41.571350000   1.278060152   1.278060152
1  1  0.000000000   0.000000000   0.000000000
2  1  1.807450000   1.278060152   1.278060152
3  1  3.614900000   0.000000000   0.000000000
4  1  5.422350000   1.278060152   1.278060152
5  1  7.229800000   0.000000000   0.000000000
6  1  9.037250000   1.278060152   1.278060152
7  1  10.844700000   0.000000000   0.000000000
8  1  12.652150000   1.278060152   1.278060152
9  1  14.459600000   0.000000000   0.000000000
10  1  16.267050000   1.278060152   1.278060152
11  1  18.074500000   0.000000000   0.000000000
12  1  19.881950000   1.278060152   1.278060152
1  1  43.378800000   0.000000000   0.000000000
2  1  45.186250000   1.278060152   1.278060152
3  1  46.993700000   0.000000000   0.000000000
4  1  48.801150000   1.278060152   1.278060152
5  1  50.608600000   0.000000000   0.000000000
6  1  52.416050000   1.278060152   1.278060152
7  1  54.223500000   0.000000000   0.000000000
8  1  56.030950000   1.278060152   1.278060152
9  1  57.838400000   0.000000000   0.000000000
10  1  59.645850000   1.278060152   1.278060152
11  1  61.453300000   0.000000000   0.000000000
12  1  63.260750000   1.278060152   1.278060152
   0.000000000000000E+000  0.000000000000000E+000  0.000000000000000E+000
   65.068200000   0.000000000   0.000000000
   0.000000000   2.556120303   0.000000000
   0.000000000   0.000000000   2.556120303
####################################

I used the slater-koster files of Au-Au from  
http://www.dftb.org/parameters/download/auorg/auorg-1-1-cc/

I issued dftb+ and it runs without error. But in the output  
tunneling.dat, all the transmission numbers are 0.00.
I also tried using scc calculation, and the results are the same. All  
the transmission are 0.00

When I run the DFTB+ Tutorial on 2D Carbon Materials, it can get the  
correct results(repeating the tutorial's result). So I think the code  
itself is compiled correctly.

Could you give me some ideas about this problem? Did I set the  
structure or some calculation parameters wrong? Thank you very much!

Best,
Yuefei

-- 
Yuefei Huang
Graduate Student
Department of Material Science and NanoEngineering
Rice University
email: yuefei.huang at rice.edu
phone: +1-832-499-9169