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Wrong transmission
Date: 2013/11/11 20:17
Name: yugd   <yugd12@mails.jlu.edu.cn>

Hollow:

I want to calculation the transmission of a two dimensional system(a graphene sheet with a line defect embedded).
I calculate the two leads firstly with the files of *.HSK for left and right leads output.
Then calculate the open system with the negf, at last using the TranMain i get the transmission, but the transmission is incorrect obviously. Please help me correct my errors, thanks in advance.

some import parameters（not all due to the limitation of the total number of the characters） were given below：


my left lead;

NEGF.output_hks on
NEGF.filename.hks left-lead.hks
NEGF.Output.for.TranMain off


Species.Number 1
<Definition.of.Atomic.Species
C C5.0-s2p2 C_PBE13
Definition.of.Atomic.Species>

<Atoms.UnitVectors
4.9237868970192151 0.0000000000 0.0000000000
0.0000000000 22.7240009308 0.0000000000
0.0000000000 0.0000000000 15.0000000000
Atoms.UnitVectors>

scf.XcType GGA-PBE # LDA|LSDA-CA|LSDA-PW
scf.SpinPolarization On # On|Off
scf.ElectronicTemperature 300.0 # default=300 (K)
scf.energycutoff 300.0 # default=150 (Ry)
scf.maxIter 100 # default=40
scf.EigenvalueSolver band # Recursion|Cluster|Band
scf.lapack.dste dstevx # dstegr|dstedc|dstevx, default=dstegr
scf.Kgrid 200 2 1 # means 4x4x4
scf.Mixing.Type rmm-diisk # Simple|Rmm-Diis|Gr-Pulay
scf.Init.Mixing.Weight 0.010 # default=0.30
scf.Min.Mixing.Weight 0.001 # default=0.001
scf.Max.Mixing.Weight 0.200 # default=0.40
scf.Mixing.History 15 # default=5
scf.Mixing.StartPulay 5 # default=6
scf.criterion 1.0e-8 # default=1.0e-6 (Hartree)


my right lead：

NEGF.output_hks on
NEGF.filename.hks right-lead.hks
NEGF.Output.for.TranMain off


Species.Number 1
<Definition.of.Atomic.Species
C C5.0-s2p2 C_PBE13
Definition.of.Atomic.Species>

Atoms.UnitVectors.Unit Ang # Ang|AU
<Atoms.UnitVectors
4.9237868970192151 0.0000000000 0.0000000000
0.0000000000 22.7240009308 0.0000000000
0.0000000000 0.0000000000 15.0000000000
Atoms.UnitVectors>


scf.XcType GGA-PBE # LDA|LSDA-CA|LSDA-PW
scf.SpinPolarization On # On|Off
scf.ElectronicTemperature 300.0 # default=300 (K)
scf.energycutoff 300.0 # default=150 (Ry)
scf.maxIter 100 # default=40
scf.EigenvalueSolver band # Recursion|Cluster|Band
scf.lapack.dste dstevx # dstegr|dstedc|dstevx, default=dstegr
scf.Kgrid 200 2 1 # means 4x4x4
scf.Mixing.Type rmm-diisk # Simple|Rmm-Diis|Gr-Pulay
scf.Init.Mixing.Weight 0.010 # default=0.30
scf.Min.Mixing.Weight 0.001 # default=0.001
scf.Max.Mixing.Weight 0.200 # default=0.40
scf.Mixing.History 15 # default=5
scf.Mixing.StartPulay 5 # default=6
scf.criterion 1.0e-8 # default=1.0e-6 (Hartree)


negf calculation：
DATA.PATH /data3/home/yugd/workplace/yugd/openmx/DFT_DATA13
System.CurrrentDirectory ./ # default=./
System.Name CrH8-negf-ELD
level.of.stdout 1 # default=1 (1-3)
level.of.fileout 0 # default=1 (1-3)

NEGF.filename.hks.l left-lead.hks
NEGF.filename.hks.r right-lead.hks

NEGF.Num.Poles 150 # defalut=150
NEGF.scf.Kgrid 2 1 # defalut=1 1

NEGF.bias.voltage 0.0 # default=0.0 (eV)
NEGF.bias.neq.im.energy 0.01 # default=0.01 (eV)
NEGF.bias.neq.energy.step 0.02 # default=0.02 (eV)


NEGF.tran.energydiv 500 # default=200
NEGF.tran.energyrange -2.0 2.0 1.0e-3 # default=-10.0 10.0 1.0e-3 (eV)
NEGF.tran.Kgrid 10 1 # default= 1 1


Species.Number 2
<Definition.of.Atomic.Species
C C5.0-s2p2 C_PBE13
Cr Cr6.0-s3p3d3 Cr_PBE13
Definition.of.Atomic.Species>


scf.XcType GGA-PBE # LDA|LSDA-CA|LSDA-PW
scf.SpinPolarization On # On|Off
scf.ElectronicTemperature 300.0 # default=300 (K)
scf.energycutoff 300.0 # default=150 (Ry)
scf.maxIter 500 # default=40
scf.EigenvalueSolver NEGF # Recursion|Cluster|Band
scf.lapack.dste dstevx # dstegr|dstedc|dstevx, default=dstegr
scf.Kgrid 1 1 1 # means 4x4x4
scf.Mixing.Type rmm-diisk # Simple|Rmm-Diis|Gr-Pulay
scf.Init.Mixing.Weight 0.010 # default=0.30
scf.Min.Mixing.Weight 0.001 # default=0.001
scf.Max.Mixing.Weight 0.200 # default=0.40
scf.Mixing.History 15 # default=5
scf.Mixing.StartPulay 5 # default=6
scf.criterion 1.0e-7 # default=1.0e-6 (Hartree)

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Re: Wrong transmission ( No.1 )
Date: 2013/11/20 21:40
Name: yugd  <yugd12@mails.jlu.edu.cn>

By calculation of the same system with different basis set, i found a question. It is that for the transport calculation with NEGF, when the smaller basis(eg. C5.0-s1p2) was used, the transmission was right(it present stepped shape), but it is incorrect obviously(the transmission presented many sharp peaks) when using the bigger basis set(C5.0-s2p2d2). But when i used the big basis set, and meanwhile the unit cell of the lead was doubled, the transmission will be right and almost agree with the result of the small basis. The question can appear in not only OpenMX but also transiesta. I don't know why.
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