Thank you very much. Do you mean I should add buffer layers or I must
only increase the width of my electrodes further?

On 10/1/15, Nick Papior <[email protected]> wrote:
> You may have a longer ranging screening length of your electrode.
>
> Try and add more electrode layers. Generally you just want dQ to be as low
> as possible, but sometimes it can be hard.
>
> See answer below:
>
> 2015-10-01 11:04 GMT+02:00 Seyed Mohammad Tabatabaei <[email protected]>:
>
>> Dear all,
>>
>> I have attached the three last steps of my transiesta convergence at 0
>> Volts bias. Even at this bias, there exists a difference beween Qsol
>> and Qtot.
>>
>> Is this difference which is equal to 0.337 tolerable?
>>
>> Is there any method to assess the maximum tolerable difference in my
>> calculation? Does it cause my calculated currents to become invalid or
>> in any case the convergence is reached, the currents are valid?
>>
>> I have read many previous threads about this on the forum. In case my
>> questions are answered in some threads, I would be really grateful if
>> someone send the links.
>>
>> TranSiesta: Qsol,Qtot: 1008.337 1008.000    1.000
>> transiesta:  20   -49567.1342   -49567.1262   -49567.1262  0.0003 -3.0035
>> TranSiesta: Qsol,Qtot: 1008.338 1008.000    1.000
>> transiesta:  21   -49567.1436   -49567.1348   -49567.1348  0.0002 -3.0035
>> TranSiesta: Qsol,Qtot: 1008.339 1008.000    1.000
>> transiesta:  22   -49567.1335   -49567.1341   -49567.1341  0.0001 -3.0035
>> TranSiesta: Qsol,Qtot: 1008.339 1008.000    1.000
>> transiesta:  23   -49567.1320   -49567.1330   -49567.1330  0.0001 -3.0035
>>
>> One other critical question for me is that how should I know my Qtot
>> is correct? The parameters below are used in my calculation. The width
>> of my electrodes are about 11 Angstroms which guarantees nearest
>> neighbor only interactions. Is it correct that I increase the
>> TS.ComplexContour.NPoles, TS.ComplexContour.NCircle,
>> TS.ComplexContour.NLine, and TS.biasContour.NumPoints all by one and
>> see if Qtot is still equal to 1008.000? Is this what is called
>> convergence test?
>>
> Yes.
> And adding more electrode layers can/is also part of the convergence test.
>
>>
>> Best wishes,
>> Mohammad,
>>
>> SystemName    scat
>> SystemLabel     scat
>> %block kgrid_Monkhorst_Pack
>>   6   0   0    0.0
>>   0   1   0    0.0
>>   0   0   3    0.0
>> %endblock kgrid_Monkhorst_Pack
>> xc.functional           GGA
>> xc.authors              PBE
>> MeshCutoff              300.0 Ry
>> SolutionMethod          transiesta
>> OccupationFunction      MP
>> ElectronicTemperature   300 K
>> MaxSCFIterations        300
>> DM.NumberPulay          6
>> DM.NumberBroyden        0
>> DM.MixingWeight         0.1000000000
>> DM.OccupancyTolerance   0.1000000000E-11
>> DM.NumberKick           0
>> DM.KickMixingWeight     0.5000000000
>> DM.Tolerance            0.1000000000E-03
>> UseSaveData             T
>> DM.UseSaveDM            T
>> ON.UseSaveLWF           T
>> MD.UseSaveXV            T
>> MD.UseSaveCG            T
>> MD.NumCGsteps           0
>> MD.TypeOfRun            CG
>> MD.VariableCell         F
>> MD.MaxCGDispl           0.2000000000  Bohr
>> MD.MaxForceTol          0.02 eV/Ang
>> PAO.SplitNorm           0.15392
>> PAO.BasisSize           DZP
>> %include POSITIONS.fdf
>> # transiesta information
>> TS.MixH                         T
>> # GENGF OPTIONS
>> TS.ComplexContour.Emin         -28 eV
>> TS.ComplexContour.NPoles        16
>> TS.ComplexContour.NCircle       16
>> TS.ComplexContour.NLine         10
>> # BIAS OPTIONS
>> TS.biasContour.NumPoints        10
>> TS.BiasContour.Eta              0.000001 Ry
>> # TS OPTIONS
>> TS.Voltage 0.0 eV
>> # TBT OPTIONS
>> TS.TBT.Emin                     -3 eV
>> TS.TBT.Emax                     +3 eV
>> TS.TBT.NPoints                  500
>> TS.TBT.NEigen                   3
>> TS.TBT.Eta                      0.000001 Ry
>> # Write electrode hamiltonian
>> TS.SaveHS   .true.
>> TS.SaveLead .true.
>> # LEFT ELECTRODE
>> TS.HSFileLeft  ./elec.TSHS
>> TS.NumUsedAtomsLeft   48
>> TS.BufferAtomsLeft    0
>> # RIGHT ELECTRODE
>> TS.HSFileRight  ./elec.TSHS
>> TS.NumUsedAtomsRight  48
>> TS.BufferAtomsRight   0
>>
>
>
>
> --
> Kind regards Nick
>

Responder a