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NEGF issues
Date: 2020/04/03 05:26
Name: Luca Sementa

Dear Developers

I am trying to calculate the transmission of NbS2-WSe2 interfaces. For small systems the NEGF converges in few steps also with different basis sets.
When the system is the one attached below, the calculation does not converge. I tried by modifying several keywords (NEGF.SCF.Iter.Band, Num.Poles, Mixing.Weight and others) without success. Could you please give me some hints on how to improve the convergence?


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System.CurrrentDirectory ./ # default=./
System.Name negf-nbsws
level.of.stdout 1 # default=1 (1-3)
level.of.fileout 0 # default=1 (0-2)

NEGF.filename.hks.l l-lead-graphene.hks
NEGF.filename.hks.r l-lead-graphene.hks

NEGF.tran.SCF.skip off

NEGF.Num.Poles 150 # defalut=150
NEGF.scf.Kgrid 10 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)

Dos.fileout off # on|off, default=off
NEGF.Dos.energyrange -10.0 10.0 5.0e-3 #default=-10.0 10.0 5.0e-3 (eV)
NEGF.Dos.energy.div 600 # default=200
NEGF.Dos.Kgrid 15 1 # default=1 1
NEGF.SCF.Iter.Band 5

#
# Transmission & Eigen Channel
#

NEGF.tran.Analysis on # default on
NEGF.tran.energydiv 600 # default=200
NEGF.tran.energyrange -15.0 15.0 1.0e-3 # default=-10.0 10.0 1.0e-3 (eV)
NEGF.tran.Kgrid 20 1 # default= 1 1
NEGF.tran.Channel off # default on
NEGF.Channel.Nkpoint 1 # default=1
<NEGF.Channel.kpoint
0.0 0.0
NEGF.Channel.kpoint>
# default 0.0 0.0
NEGF.Channel.Nenergy 1 # default=1
<NEGF.Channel.energy
0.0
NEGF.Channel.energy>
# default 0.0
NEGF.Channel.Num 5 # defualt=5(for collinear), 10(for Non-collinear)

#
# Definition of Atomic Species
#

Species.Number 4
<Definition.of.Atomic.Species
W W7.0-s3p2d W_PBE19
Nb Nb7.0-s3p2d Nb_PBE19
S S7.0-s2p2d S_PBE19
Se Se7.0-s3p2d Se_PBE19
Definition.of.Atomic.Species>
DATA.PATH /DFT_DATA19/
#
# Atoms
#

Atoms.Number 96
Atoms.SpeciesAndCoordinates.Unit Ang # Ang|AU
<Atoms.SpeciesAndCoordinates
1 Nb 10.92924060 0.00000000 0.00000000 6.5 6.5
2 S 11.84001065 1.57750000 1.59315000 3.0 3.0
3 S 11.84001065 1.57750000 -1.59315000 3.0 3.0
4 Nb 13.66155074 1.57750000 0.00000000 6.5 6.5
5 S 14.57232079 0.00000000 1.59315000 3.0 3.0
6 S 14.57232079 0.00000000 -1.59315000 3.0 3.0
7 Nb 16.39386089 0.00000000 0.00000000 6.5 6.5
8 S 17.30463094 1.57750000 1.59315000 3.0 3.0
9 S 17.30463094 1.57750000 -1.59315000 3.0 3.0
10 Nb 19.12617104 1.57750000 0.00000000 6.5 6.5
11 S 20.03694109 0.00000000 1.59315000 3.0 3.0
12 S 20.03694109 0.00000000 -1.59315000 3.0 3.0
13 Nb 21.85848119 0.00000000 0.00000000 6.5 6.5
14 S 22.76925124 1.57750000 1.59315000 3.0 3.0
15 S 22.76925124 1.57750000 -1.59315000 3.0 3.0
16 Nb 24.59079134 1.57750000 0.00000000 6.5 6.5
17 S 25.50156139 0.00000000 1.59315000 3.0 3.0
18 S 25.50156139 0.00000000 -1.59315000 3.0 3.0
19 Nb 27.32310149 0.00000000 0.00000000 6.5 6.5
20 S 28.23387154 1.57750000 1.59315000 3.0 3.0
21 S 28.23387154 1.57750000 -1.59315000 3.0 3.0
22 Nb 30.05541164 1.57750000 0.00000000 6.5 6.5
23 S 30.96618169 0.00000000 1.59315000 3.0 3.0
24 S 30.96618169 0.00000000 -1.59315000 3.0 3.0
25 W 32.78772179 0.00000000 0.00000000 6.0 6.0
26 Se 33.69849184 1.57750000 1.59315000 3.0 3.0
27 Se 33.69849184 1.57750000 -1.59315000 3.0 3.0
28 W 35.52003194 1.57750000 0.00000000 6.0 6.0
29 Se 36.43080199 0.00000000 1.59315000 3.0 3.0
30 Se 36.43080199 0.00000000 -1.59315000 3.0 3.0
31 W 38.25234209 0.00000000 0.00000000 6.0 6.0
32 Se 39.16311214 1.57750000 1.59315000 3.0 3.0
33 Se 39.16311214 1.57750000 -1.59315000 3.0 3.0
34 W 40.98465223 1.57750000 0.00000000 6.0 6.0
35 Se 41.89542229 0.00000000 1.59315000 3.0 3.0
36 Se 41.89542229 0.00000000 -1.59315000 3.0 3.0
37 W 43.71696238 0.00000000 0.00000000 6.0 6.0
38 Se 44.62773243 1.57750000 1.59315000 3.0 3.0
39 Se 44.62773243 1.57750000 -1.59315000 3.0 3.0
40 W 46.44927253 1.57750000 0.00000000 6.0 6.0
41 Se 47.36004258 0.00000000 1.59315000 3.0 3.0
42 Se 47.36004258 0.00000000 -1.59315000 3.0 3.0
43 W 49.18158268 0.00000000 0.00000000 6.0 6.0
44 Se 50.09235273 1.57750000 1.59315000 3.0 3.0
45 Se 50.09235273 1.57750000 -1.59315000 3.0 3.0
46 W 51.91389283 1.57750000 0.00000000 6.0 6.0
47 Se 52.82466288 0.00000000 1.59315000 3.0 3.0
48 Se 52.82466288 0.00000000 -1.59315000 3.0 3.0
49 W 54.64620298 0.00000000 0.00000000 6.0 6.0
50 Se 55.55697303 1.57750000 1.59315000 3.0 3.0
51 Se 55.55697303 1.57750000 -1.59315000 3.0 3.0
52 W 57.37851313 1.57750000 0.00000000 6.0 6.0
53 Se 58.28928318 0.00000000 1.59315000 3.0 3.0
54 Se 58.28928318 0.00000000 -1.59315000 3.0 3.0
55 W 60.11082328 0.00000000 0.00000000 6.0 6.0
56 Se 61.02159333 1.57750000 1.59315000 3.0 3.0
57 Se 61.02159333 1.57750000 -1.59315000 3.0 3.0
58 W 62.84313343 1.57750000 0.00000000 6.0 6.0
59 Se 63.75390348 0.00000000 1.59315000 3.0 3.0
60 Se 63.75390348 0.00000000 -1.59315000 3.0 3.0
61 W 65.57544358 0.00000000 0.00000000 6.0 6.0
62 Se 66.48621363 1.57750000 1.59315000 3.0 3.0
63 Se 66.48621363 1.57750000 -1.59315000 3.0 3.0
64 W 68.30775372 1.57750000 0.00000000 6.0 6.0
65 Se 69.21852377 0.00000000 1.59315000 3.0 3.0
66 Se 69.21852377 0.00000000 -1.59315000 3.0 3.0
67 W 71.04006387 0.00000000 0.00000000 6.0 6.0
68 Se 71.95083392 1.57750000 1.59315000 3.0 3.0
69 Se 71.95083392 1.57750000 -1.59315000 3.0 3.0
70 W 73.77237402 1.57750000 0.00000000 6.0 6.0
71 Se 74.68314407 0.00000000 1.59315000 3.0 3.0
72 Se 74.68314407 0.00000000 -1.59315000 3.0 3.0
73 Nb 76.50468417 0.00000000 0.00000000 6.5 6.5
74 S 77.41545422 1.57750000 1.59315000 3.0 3.0
75 S 77.41545422 1.57750000 -1.59315000 3.0 3.0
76 Nb 79.23699432 1.57750000 0.00000000 6.5 6.5
77 S 80.14776437 0.00000000 1.59315000 3.0 3.0
78 S 80.14776437 0.00000000 -1.59315000 3.0 3.0
79 Nb 81.96930447 0.00000000 0.00000000 6.5 6.5
80 S 82.88007452 1.57750000 1.59315000 3.0 3.0
81 S 82.88007452 1.57750000 -1.59315000 3.0 3.0
82 Nb 84.70161462 1.57750000 0.00000000 6.5 6.5
83 S 85.61238467 0.00000000 1.59315000 3.0 3.0
84 S 85.61238467 0.00000000 -1.59315000 3.0 3.0
85 Nb 87.43392477 0.00000000 0.00000000 6.5 6.5
86 S 88.34469482 1.57750000 1.59315000 3.0 3.0
87 S 88.34469482 1.57750000 -1.59315000 3.0 3.0
88 Nb 90.16623492 1.57750000 0.00000000 6.5 6.5
89 S 91.07700497 0.00000000 1.59315000 3.0 3.0
90 S 91.07700497 0.00000000 -1.59315000 3.0 3.0
91 Nb 92.89854507 0.00000000 0.00000000 6.5 6.5
92 S 93.80931512 1.57750000 1.59315000 3.0 3.0
93 S 93.80931512 1.57750000 -1.59315000 3.0 3.0
94 Nb 95.63085521 1.57750000 0.00000000 6.5 6.5
95 S 96.54162526 0.00000000 1.59315000 3.0 3.0
96 S 96.54162526 0.00000000 -1.59315000 3.0 3.0
Atoms.SpeciesAndCoordinates>
##Device unit cell or scattering reagion ?
#Atoms.UnitVectors.Unit Ang # Ang|AU
#<Atoms.UnitVectors
# 92.4094818960 0.0000000000 0.0000000000
# 0.0000000000 3.3302451750 0.0000000000
# 0.0000000000 0.0000000000 15.0000000000
#Atoms.UnitVectors>


#
# Lead-Left
#

LeftLeadAtoms.Number 12
<LeftLeadAtoms.SpeciesAndCoordinates # Unit=Ang.
1 Nb 0.00000000 0.00000000 0.00000000 6.5 6.5
2 S 0.91077005 1.57750000 1.59315000 3.0 3.0
3 S 0.91077005 1.57750000 -1.59315000 3.0 3.0
4 Nb 2.73231015 1.57750000 0.00000000 6.5 6.5
5 S 3.64308020 0.00000000 1.59315000 3.0 3.0
6 S 3.64308020 0.00000000 -1.59315000 3.0 3.0
7 Nb 5.46462030 0.00000000 0.00000000 6.5 6.5
8 S 6.37539035 1.57750000 1.59315000 3.0 3.0
9 S 6.37539035 1.57750000 -1.59315000 3.0 3.0
10 Nb 8.19693045 1.57750000 0.00000000 6.5 6.5
11 S 9.10770050 0.00000000 1.59315000 3.0 3.0
12 S 9.10770050 0.00000000 -1.59315000 3.0 3.0
LeftLeadAtoms.SpeciesAndCoordinates>

#
# Lead-Right
#

RightLeadAtoms.Number 12
<RightLeadAtoms.SpeciesAndCoordinates # Unit=Ang.
1 Nb 98.36316536 0.00000000 0.00000000 6.5 6.5
2 S 99.27393541 1.57750000 1.59315000 3.0 3.0
3 S 99.27393541 1.57750000 -1.59315000 3.0 3.0
4 Nb 101.09547551 1.57750000 0.00000000 6.5 6.5
5 S 102.00624556 0.00000000 1.59315000 3.0 3.0
6 S 102.00624556 0.00000000 -1.59315000 3.0 3.0
7 Nb 103.82778566 0.00000000 0.00000000 6.5 6.5
8 S 104.73855571 1.57750000 1.59315000 3.0 3.0
9 S 104.73855571 1.57750000 -1.59315000 3.0 3.0
10 Nb 106.56009581 1.57750000 0.00000000 6.5 6.5
11 S 107.47086586 0.00000000 1.59315000 3.0 3.0
12 S 107.47086586 0.00000000 -1.59315000 3.0 3.0
RightLeadAtoms.SpeciesAndCoordinates>

#
# SCF or Electronic System
#
scf.restart off
scf.system.charge 0.0


scf.XcType GGA-PBE # LDA|LSDA-CA|LSDA-PW|GGA-PBE
scf.SpinPolarization off # On|Off|NC
scf.ElectronicTemperature 300.0 # default=300 (K)
scf.energycutoff 200.0 # default=150 (Ry)
scf.maxIter 500 # default=40
scf.EigenvalueSolver NEGF # DC|GDC|Cluster|Band
scf.lapack.dste dstevx # dstegr|dstedc|dstevx, default=dstegr
scf.Kgrid 10 10 1 # means n1 x n2 x n3
scf.Mixing.Type Rmm-Diisk # Simple|Rmm-Diis|Gr-Pulay|Kerker|Rmm-Diisk
scf.Init.Mixing.Weight 0.010 # default=0.30
scf.Min.Mixing.Weight 0.005 # default=0.001
scf.Max.Mixing.Weight 0.010 # default=0.40
scf.Mixing.History 50 # default=5
scf.Mixing.StartPulay 20 # default=6
scf.Mixing.EveryPulay 1 # default=6
scf.criterion 1.0e-05 # default=1.0e-6 (Hartree)

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Luca

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