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
