Transport calculation of Fe|MgO|Fe |
- Date: 2022/07/20 23:31
- Name: Wuzhang Fang
<wfang@huskers.unl.edu>
- Dear OpenMX users and developers,
I tried to perform transport calculations of an MTJ Fe|MgO(6ML)|Fe. I took the structure from this ATK tutorial as I wanted to compare the results with theirs (https://docs.quantumatk.com/tutorials/fe_mgo_fe/fe_mgo_fe.html). Please find my input file for NEGF calculations in the end. I got pretty similar features of the k-resolved transmission. The total conductances in the unit of e^2/h are 9.15e-05 and 1.65e-06 for spin-up and down channels. The total conductances from the ATK tutorial are 1.06e-04 and 7.20e-06 for spin-up and down channels. The difference may come from the choice of basis sets or kpoints convergence.
Has anyone ever performed similar transport calculations of Fe|MgO|Fe using OpenMX? If so, could you kindly share your results, i.e. total conductances or input file? Any comments on performing reliable transport calculations using OpenMX are very welcome.
Thanks,
Wuzhang Fang
---------------------------------------------
#
# File Name
#
System.CurrrentDirectory ./ # default=./
System.Name negf-femgo
level.of.stdout 1 # default=1 (1-3)
level.of.fileout 0 # default=1 (0-2)
NEGF.filename.hks.l lead-femgo.hks
NEGF.filename.hks.r lead-femgo.hks
NEGF.Num.Poles 100 # defalut=150
NEGF.scf.Kgrid 12 12 # 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 -15.0 25.0 5.0e-3 #default=-10.0 10.0 5.0e-3 (eV)
NEGF.Dos.energy.div 200 # default=200
NEGF.Dos.Kgrid 600 600 # default=1 1
NEGF.SCF.Iter.Band 20
#
# Transmission & Eigen Channel
#
NEGF.tran.Analysis on # default on
NEGF.tran.energydiv 3 # default=200
NEGF.tran.energyrange -0.1 0.1 1.0e-3 # default=-10.0 10.0 1.0e-3 (eV)
NEGF.tran.Kgrid 151 151 # 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 3
<Definition.of.Atomic.Species
Fe Fe6.0S-s3p3d2 Fe_PBE19S
Mg Mg7.0-s3p3d2 Mg_PBE19
O O5.0-s2p2d1 O_PBE19
Definition.of.Atomic.Species>
#
# Atoms
#
Atoms.Number 16
Atoms.SpeciesAndCoordinates.Unit Ang # Ang|AU
<Atoms.SpeciesAndCoordinates
1 Fe 6.461176916299 0.7165 0.7165 8.5 5.5
2 Fe 7.883348084818 2.1495 2.1495 8.5 5.5
3 Mg 10.046913166035 0.7165 0.7165 4.0 4.0
4 O 10.125854994682 2.1495 2.1495 3.0 3.0
5 O 12.2742460054 0.7165 0.7165 3.0 3.0
6 Mg 12.287565384199 2.1495 2.1495 4.0 4.0
7 Mg 14.47251361208 0.7165 0.7165 4.0 4.0
8 O 14.47501183558 2.1495 2.1495 3.0 3.0
9 O 16.667197114 0.7165 0.7165 3.0 3.0
10 Mg 16.669729913304 2.1495 2.1495 4.0 4.0
11 Mg 18.854675912015 0.7165 0.7165 4.0 4.0
12 O 18.867967064779 2.1495 2.1495 3.0 3.0
13 O 21.016369375396 0.7165 0.7165 3.0 3.0
14 Mg 21.095331583047 2.1495 2.1495 4.0 4.0
15 Fe 23.258901803911 0.7165 0.7165 8.5 5.5
16 Fe 24.681132523465 2.1495 2.1495 8.5 5.5
Atoms.SpeciesAndCoordinates>
#
# Lead-Left
#
LeftLeadAtoms.Number 4
<LeftLeadAtoms.SpeciesAndCoordinates # Unit=Ang.
1 Fe 0.716499999992 0.716500000003 0.716500000003 8.5 5.5
2 Fe 2.149500000008 2.149500000003 2.149500000003 8.5 5.5
3 Fe 3.582499999992 0.716500000003 0.716500000003 8.5 5.5
4 Fe 5.015500000008 2.149500000003 2.149500000003 8.5 5.5
LeftLeadAtoms.SpeciesAndCoordinates>
#
# Lead-Right
#
RightLeadAtoms.Number 4
<RightLeadAtoms.SpeciesAndCoordinates # Unit=Ang.
1 Fe 26.124249999992 0.716500000003 0.716500000003 8.5 5.5
2 Fe 27.557250000008 2.149500000003 2.149500000003 8.5 5.5
3 Fe 28.990249999992 0.716500000003 0.716500000003 8.5 5.5
4 Fe 30.423250000008 2.149500000003 2.149500000003 8.5 5.5
RightLeadAtoms.SpeciesAndCoordinates>
#
# SCF or Electronic System
#
scf.XcType GGA-PBE # LDA|LSDA-CA|LSDA-PW|GGA-PBE
scf.SpinPolarization on # On|Off|NC
scf.ElectronicTemperature 600.0 # default=300 (K)
scf.energycutoff 200.0 # default=150 (Ry)
scf.maxIter 400 # default=40
scf.EigenvalueSolver NEGF # DC|GDC|Cluster|Band
#scf.lapack.dste dstevx # dstegr|dstedc|dstevx, default=dstegr
scf.Kgrid 200 12 12 # 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 0.001 # default=0.001
scf.Max.Mixing.Weight 0.100 # default=0.40
scf.Mixing.History 40 # default=5
scf.Mixing.StartPulay 10 # default=6
#scf.Kerker.factor 1.0 # default=1.0
scf.criterion 1.0e-7 # default=1.0e-6 (Hartree)
scf.restart on # on|off,default=off
 | |
This thread is locked.Only browsing is available.
Re: Transport calculation of Fe|MgO|Fe