Dear Everybody

I am trying to obtain the transmission spectrum of a metallic carbon nanotube (8,8), carried out with Transiesta code. Unfortunately I don’t get the right spectrum (normally at the Fermi level I should see two conduction channels appear, I have attached the file). I have changed the settings several times but the result is never correct. In the following there is my input files for the electrodes and the scattering zone. Could you please check if one of my parameters is wrong or if I forgot something?
Thank you very much for your help.
Best regards.

Damien


*Electrode :*


# General system descriptors
SystemName              cnt
SystemLabel             cnt
NumberOfAtoms           32
NumberOfSpecies         1
%block ChemicalSpeciesLabel
 1  6 C.gga   # Species index, atomic number, species label
%endblock ChemicalSpeciesLabel

#Unit cell for the calculation
LatticeConstant 1 Ang
%block LatticeVectors
30.0000000000000000  0.0000000000000000  0.0000000000000000
 0.0000000000000000 30.0000000000000000  0.0000000000000000
 0.0000000000000000  0.0000000000000000  2.4617000000000000
%endblock LatticeVectors
# Lattice, coordinates, k-sampling
AtomicCoordinatesFormat Fractional
AtomicCoorFormatOut     Fractional
%block AtomicCoordinatesAndAtomicSpecies
 0.684228479       0.500102328      -0.000000000 1
 0.677959183       0.547673034       0.000000000 1
 0.670191861       0.570611130       0.500000000 1
 0.646198057       0.612161657       0.500000000 1
 0.630219773       0.630352389       0.000000000 1
 0.592119446       0.659511823      -0.000000000 1
 0.570405934       0.670221335       0.500000000 1
 0.524063557       0.682647265       0.500000001 1
 0.499897672       0.684228479      -0.000000000 1
 0.452326966       0.677959184      -0.000000000 1
 0.429388870       0.670191860       0.500000000 1
 0.387838343       0.646198057       0.500000000 1
 0.369647610       0.630219773       0.000000000 1
 0.340488177       0.592119446      -0.000000000 1
 0.329778665       0.570405934       0.500000000 1
 0.317352735       0.524063557       0.500000000 1
 0.315771521       0.499897672       0.000000000 1
 0.322040816       0.452326966      -0.000000000 1
 0.329808140       0.429388870       0.500000000 1
 0.353801943       0.387838343       0.500000000 1
 0.369780227       0.369647611      -0.000000000 1
 0.407880554       0.340488177       0.000000000 1
 0.429594066       0.329778665       0.499999999 1
 0.475936443       0.317352735       0.500000001 1
 0.500102328       0.315771521      -0.000000000 1
 0.547673034       0.322040816      -0.000000000 1
 0.570611130       0.329808139       0.500000001 1
 0.612161657       0.353801943       0.500000000 1
 0.630352390       0.369780227      -0.000000000 1
 0.659511823       0.407880554      -0.000000000 1
 0.670221335       0.429594066       0.500000000 1
 0.682647265       0.475936443       0.500000000 1
%endblock AtomicCoordinatesAndAtomicSpecies

# K-sampling (alternative specification using kgrid_cutoff)
%block kgrid_Monkhorst_Pack
 1   0   0   0.0
 0   1   0   0.0
 0   0   100 0.0
%endblock kgrid_Monkhorst_Pack

# Basis set definition
PAO.BasisSize   DZP
PAO.EnergyShift 50 meV
PAO.SplitNorm   0.15

# Real space grid
MeshCutoff 200.0 Ry

#Convergence of SCF
MaxSCFIterations 100
DM.MixingWeight  0.05
DM.NumberPulay   10
DM.Tolerance     0.0001

# Eigenvalue problem: order-N or diagonalization
SolutionMethod          diagon
ElectronicTemperature   5.0 K


# Density functional (Notice that Xc.authors and XC.functional)
XC.functional           VDW
XC.authors              KBM

# Molecular Dynamics and relaxations
MD.TypeOfRun            CG
MD.NumCGsteps           0
MD.VariableCell         .false.
MD.ConstantVolume       .true.

# Output options
WriteCoorInitial        .false.
WriteCoorStep           .true.
WriteForces             .false.
WriteKpoints            .false.
WriteEigenvalues        .false.
WriteDM                 .true.
WriteKbands             .false.
WriteBands              .false.
WriteWaveFunctions      .true.
WriteMullikenPop        0
WriteCoorXmol           .true.
WriteCoorCerius         .true.
WriteMDXmol             .true.
WriteMDhistory          .true.

*Scattering zone :*

# General system descriptors
SystemName              cnt-system
SystemLabel             cnt-system
NumberOfAtoms           96
NumberOfSpecies         1
%block ChemicalSpeciesLabel
 1  6 C.gga   # Species index, atomic number, species label
%endblock ChemicalSpeciesLabel

#Unit cell for the calculation
LatticeConstant 1 Ang
%block LatticeVectors
30.0000000000000000  0.0000000000000000  0.0000000000000000
 0.0000000000000000 30.0000000000000000  0.0000000000000000
 0.0000000000000000  0.0000000000000000  7.3851000000000000
%endblock LatticeVectors
# Lattice, coordinates, k-sampling
AtomicCoordinatesFormat Fractional
AtomicCoorFormatOut     Fractional
%block AtomicCoordinatesAndAtomicSpecies
  0.6842284789999999  0.5001023280000000  0.0000000000000000 1
  0.6779591830000000  0.5476730340000000  0.0000000000000000 1
  0.6701918610000001  0.5706111300000000  0.1666666666666667 1
  0.6461980570000000  0.6121616570000000  0.1666666666666667 1
  0.6302197730000000  0.6303523890000000  0.0000000000000000 1
  0.5921194460000000  0.6595118230000000  0.0000000000000000 1
  0.5704059339999999  0.6702213350000000  0.1666666666666667 1
  0.5240635570000000  0.6826472649999999  0.1666666670000000 1
  0.4998976720000000  0.6842284789999999  0.0000000000000000 1
  0.4523269660000000  0.6779591840000000  0.0000000000000000 1
  0.4293888700000000  0.6701918600000000  0.1666666666666667 1
  0.3878383430000000  0.6461980570000000  0.1666666666666667 1
  0.3696476100000000  0.6302197730000000  0.0000000000000000 1
  0.3404881770000000  0.5921194460000000  0.0000000000000000 1
  0.3297786650000000  0.5704059339999999  0.1666666666666667 1
  0.3173527350000000  0.5240635570000000  0.1666666666666667 1
  0.3157715210000000  0.4998976720000000  0.0000000000000000 1
  0.3220408160000000  0.4523269660000000  0.0000000000000000 1
  0.3298081400000000  0.4293888700000000  0.1666666666666667 1
  0.3538019430000000  0.3878383430000000  0.1666666666666667 1
  0.3697802270000000  0.3696476110000000  0.0000000000000000 1
  0.4078805540000000  0.3404881770000000  0.0000000000000000 1
  0.4295940660000000  0.3297786650000000  0.1666666663333333 1
  0.4759364430000000  0.3173527350000000  0.1666666670000000 1
  0.5001023280000000  0.3157715210000000  0.0000000000000000 1
  0.5476730340000000  0.3220408160000000  0.0000000000000000 1
  0.5706111300000000  0.3298081390000000  0.1666666670000000 1
  0.6121616570000000  0.3538019430000000  0.1666666666666667 1
  0.6303523900000000  0.3697802270000000  0.0000000000000000 1
  0.6595118230000000  0.4078805540000000  0.0000000000000000 1
  0.6702213350000000  0.4295940660000000  0.1666666666666667 1
  0.6826472649999999  0.4759364430000000  0.1666666666666667 1
  0.6842284789999999  0.5001023280000000  0.3333333333333333 1
  0.6779591830000000  0.5476730340000000  0.3333333333333333 1
  0.6701918610000001  0.5706111300000000  0.5000000000000000 1
  0.6461980570000000  0.6121616570000000  0.5000000000000000 1
  0.6302197730000000  0.6303523890000000  0.3333333333333333 1
  0.5921194460000000  0.6595118230000000  0.3333333333333333 1
  0.5704059339999999  0.6702213350000000  0.5000000000000000 1
  0.5240635570000000  0.6826472649999999  0.5000000003333334 1
  0.4998976720000000  0.6842284789999999  0.3333333333333333 1
  0.4523269660000000  0.6779591840000000  0.3333333333333333 1
  0.4293888700000000  0.6701918600000000  0.5000000000000000 1
  0.3878383430000000  0.6461980570000000  0.5000000000000000 1
  0.3696476100000000  0.6302197730000000  0.3333333333333333 1
  0.3404881770000000  0.5921194460000000  0.3333333333333333 1
  0.3297786650000000  0.5704059339999999  0.5000000000000000 1
  0.3173527350000000  0.5240635570000000  0.5000000000000000 1
  0.3157715210000000  0.4998976720000000  0.3333333333333333 1
  0.3220408160000000  0.4523269660000000  0.3333333333333333 1
  0.3298081400000000  0.4293888700000000  0.5000000000000000 1
  0.3538019430000000  0.3878383430000000  0.5000000000000000 1
  0.3697802270000000  0.3696476110000000  0.3333333333333333 1
  0.4078805540000000  0.3404881770000000  0.3333333333333333 1
  0.4295940660000000  0.3297786650000000  0.4999999996666666 1
  0.4759364430000000  0.3173527350000000  0.5000000003333334 1
  0.5001023280000000  0.3157715210000000  0.3333333333333333 1
  0.5476730340000000  0.3220408160000000  0.3333333333333333 1
  0.5706111300000000  0.3298081390000000  0.5000000003333334 1
  0.6121616570000000  0.3538019430000000  0.5000000000000000 1
  0.6303523900000000  0.3697802270000000  0.3333333333333333 1
  0.6595118230000000  0.4078805540000000  0.3333333333333333 1
  0.6702213350000000  0.4295940660000000  0.5000000000000000 1
  0.6826472649999999  0.4759364430000000  0.5000000000000000 1
  0.6842284789999999  0.5001023280000000  0.6666666666666666 1
  0.6779591830000000  0.5476730340000000  0.6666666666666666 1
  0.6701918610000001  0.5706111300000000  0.8333333333333334 1
  0.6461980570000000  0.6121616570000000  0.8333333333333334 1
  0.6302197730000000  0.6303523890000000  0.6666666666666666 1
  0.5921194460000000  0.6595118230000000  0.6666666666666666 1
  0.5704059339999999  0.6702213350000000  0.8333333333333334 1
  0.5240635570000000  0.6826472649999999  0.8333333336666667 1
  0.4998976720000000  0.6842284789999999  0.6666666666666666 1
  0.4523269660000000  0.6779591840000000  0.6666666666666666 1
  0.4293888700000000  0.6701918600000000  0.8333333333333334 1
  0.3878383430000000  0.6461980570000000  0.8333333333333334 1
  0.3696476100000000  0.6302197730000000  0.6666666666666666 1
  0.3404881770000000  0.5921194460000000  0.6666666666666666 1
  0.3297786650000000  0.5704059339999999  0.8333333333333334 1
  0.3173527350000000  0.5240635570000000  0.8333333333333334 1
  0.3157715210000000  0.4998976720000000  0.6666666666666666 1
  0.3220408160000000  0.4523269660000000  0.6666666666666666 1
  0.3298081400000000  0.4293888700000000  0.8333333333333334 1
  0.3538019430000000  0.3878383430000000  0.8333333333333334 1
  0.3697802270000000  0.3696476110000000  0.6666666666666666 1
  0.4078805540000000  0.3404881770000000  0.6666666666666666 1
  0.4295940660000000  0.3297786650000000  0.8333333330000000 1
  0.4759364430000000  0.3173527350000000  0.8333333336666667 1
  0.5001023280000000  0.3157715210000000  0.6666666666666666 1
  0.5476730340000000  0.3220408160000000  0.6666666666666666 1
  0.5706111300000000  0.3298081390000000  0.8333333336666667 1
  0.6121616570000000  0.3538019430000000  0.8333333333333334 1
  0.6303523900000000  0.3697802270000000  0.6666666666666666 1
  0.6595118230000000  0.4078805540000000  0.6666666666666666 1
  0.6702213350000000  0.4295940660000000  0.8333333333333334 1
  0.6826472649999999  0.4759364430000000  0.8333333333333334 1
%endblock AtomicCoordinatesAndAtomicSpecies

# K-sampling (alternative specification using kgrid_cutoff)
%block kgrid_Monkhorst_Pack
 1   0   0   0.0
 0   1   0   0.0
 0   0   70  0.0
%endblock kgrid_Monkhorst_Pack

# Basis set definition
PAO.BasisSize   DZP
PAO.EnergyShift 50 meV
PAO.SplitNorm   0.15

# Real space grid
MeshCutoff 200.0 Ry

#Convergence of SCF
MaxSCFIterations 100
DM.MixingWeight  0.05
DM.NumberPulay   10
DM.Tolerance     0.0001
DM.UseSaveDM     .true.

# Eigenvalue problem: order-N or diagonalization
SolutionMethod          transiesta
ElectronicTemperature   5.0 K

TS.WriteHS  .true.
TS.NumUsedAtomsLeft  32
TS.NumUsedAtomsRight 32
TS.HSFileLeft   'cnt.TSHS'
TS.HSFileRight  'cnt.TSHS'
TS.TBT.HSFile   'cnt-system.TSHS'
TS.TBT.Emin    -4.0 eV
TS.TBT.Emax     4.0 eV
TS.TBT.NPoints   200

# Density functional (Notice that Xc.authors and XC.functional)
XC.functional           VDW
XC.authors              KBM

# Molecular Dynamics and relaxations
MD.TypeOfRun            CG
MD.NumCGsteps           0
MD.VariableCell         .false.
MD.ConstantVolume       .true.
# Output options
WriteCoorInitial        .false.
WriteCoorStep           .true.
WriteForces             .false.
WriteKpoints            .false.
WriteEigenvalues        .false.
WriteDM                 .true.
WriteKbands             .false.
WriteBands              .false.
WriteWaveFunctions      .true.
WriteMullikenPop        0
WriteCoorXmol           .true.
WriteCoorCerius         .true.
WriteMDXmol             .true.
WriteMDhistory          .true.

Attachment: Transmission.pdf
Description: Adobe PDF document

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