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Controlling SOC strength
Date: 2018/11/21 11:25
Name: jhong   <sequoia07@postech.ac.kr>

Dear openMX developers & users,

Hi, I am trying to calculate electronic structure of Au/W(110) system with and without spin-orbit coupling.
I want to turn on/off SOC effect individually for each atom like A. Shikin et al. did in their work (http://iopscience.iop.org/article/10.1088/1367-2630/15/9/095005/meta).
(I know they did their calculation using Wien2k code, but I would like to do the same thing using openMX code for further analysis.)

So I tried to control spin-orbit coupling strength using scf.SO.factor keyword in the input file:
scf.SpinOrbit.Coupling on
<scf.SO.factor
W s 0.0 p 0.0 d 0.0 f 0.0
Au s 1.0 p 1.0 d 1.0 f 1.0
scf.SO.factor>


By using this, I expected to switch on SOC for Au and switch off SOC for W, but the result was just exactly same for band structure considering SOC for all atoms.

So I would like to ask if it is possible to switch on/off SOC individually for each atom,
and if so, how can I do that?

Thank you.
メンテ
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Re: Controlling SOC strength ( No.1 )
Date: 2018/11/21 14:47
Name: Chi-Cheng

Hello,

I also use the same way to control the strength of SOC. When you say the results
are the same as considering SOC for all atoms, do you mean you can see
the same band splitting due to SOC? Have you turned on "scf.SpinPolarization NC"?

Cheers,
Chi-Cheng
メンテ
Re: Controlling SOC strength ( No.2 )
Date: 2018/11/22 13:26
Name: jhong  <sequoia07@postech.ac.kr>

Hi Chi-Cheng,
Thank you for your reply.

Yes, I turned on
scf.SpinPolarization NC
and I got the same SOC band splitting in calculations considering SOC effect for all atoms and only for Au atoms. (Actually the band structures were "exactly" the same.)
Did you get the expected result with using the same way to control the strength SOC? I would like to be sure if I am doing the thing in the right way.
メンテ
Re: Controlling SOC strength ( No.3 )
Date: 2018/11/22 13:44
Name: Chi-Cheng

Hi Jhong,

I think it is the right way to turn on/off the SOC. (or turn on certain percentage of SOC)
It could be the version you use is too old and therefore didn't read the input.
What is the OpenMX version you use?

Cheers,
Chi-Cheng
メンテ
Re: Controlling SOC strength ( No.4 )
Date: 2018/11/22 16:09
Name: jhong  <sequoia07@postech.ac.kr>

I am using OpenMX ver. 3.8. I don't think the version is the problem in my case.

#---------------------------------------------------------------------------------------
#
# File Name
#

System.CurrrentDirectory ./ # default=./
System.Name auw
DATA.PATH /home/disk/openmx3.8/DFT_DATA13/
level.of.stdout 1 # default=1 (1-3)
level.of.fileout 1 # default=1 (0-2)
HS.fileout on

#
# Definition of Atomic Species
#



Species.Number 2
<Definition.of.Atomic.Species
W W7.0-s2p2d1 W_PBE13
Au Au7.0-s2p2d1 Au_PBE13
Definition.of.Atomic.Species>

#
# Atoms
#

Atoms.Number 13
Atoms.SpeciesAndCoordinates.Unit FRAC # Ang|AU
<Atoms.SpeciesAndCoordinates
1 W 0.000000000 0.000000000 0.000000000 6 6 0.0 0.0 0.0 0.0 0 off
2 W 0.000000000 0.000000000 0.090908997 6 6 0.0 0.0 0.0 0.0 0 off
3 W 0.000000000 0.000000000 0.181817994 6 6 0.0 0.0 0.0 0.0 0 off
4 W 0.000000000 0.000000000 0.818181992 6 6 0.0 0.0 0.0 0.0 0 off
5 W 0.000000000 0.000000000 0.909090996 6 6 0.0 0.0 0.0 0.0 0 off
6 W 0.500000000 0.500000000 0.045455001 6 6 0.0 0.0 0.0 0.0 0 off
7 W 0.500000000 0.500000000 0.136363998 6 6 0.0 0.0 0.0 0.0 0 off
8 W 0.500000000 0.500000000 0.227273002 6 6 0.0 0.0 0.0 0.0 0 off
9 W 0.500000000 0.500000000 0.772727013 6 6 0.0 0.0 0.0 0.0 0 off
10 W 0.500000000 0.500000000 0.863636017 6 6 0.0 0.0 0.0 0.0 0 off
11 W 0.500000000 0.500000000 0.954545021 6 6 0.0 0.0 0.0 0.0 0 off
12 Au 0.000000000 0.000000000 0.272727013 8.5 8.5 0.0 0.0 0.0 0.0 0 off
13 Au 0.000000000 0.000000000 0.727272987 8.5 8.5 0.0 0.0 0.0 0.0 0 off
Atoms.SpeciesAndCoordinates>
Atoms.UnitVectors.Unit Ang # Ang|AU
<Atoms.UnitVectors
1.5792499091 -2.2333970849 0.0000000000
1.5792499091 2.2333970849 0.0000000000
0.0000000000 0.0000000000 49.1347351074
Atoms.UnitVectors>


#
# SCF or Electronic System
#

scf.restart ON
scf.XcType GGA-PBE # LDA|LSDA-CA|LSDA-PW|GGA-PBE
scf.SpinPolarization NC # On|Off|NC
scf.ElectronicTemperature 300.0 # default=300 (K)
scf.energycutoff 120.0 # default=150 (Ry)
scf.maxIter 100 # default=40
scf.EigenvalueSolver band # DC|GDC|Cluster|Band
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 0.30 # default=0.30
scf.Min.Mixing.Weight 0.001 # default=0.001
scf.Max.Mixing.Weight 0.400 # default=0.40
scf.Mixing.History 30 # default=5
scf.Mixing.EveryPulay 5
scf.Mixing.StartPulay 10 # default=6
scf.criterion 1.0e-6 # default=1.0e-6 (Hartree)
#scf.lapack.dste dstevx # dstevx|dstedc|dstegr,default=dstevx
#scf.Electric.Field 0.0 0.0 5.0 # GV/m(=0.1V/AUG)
scf.SpinOrbit.Coupling on
<scf.SO.factor
W s 0.0 p 0.0 d 0.0 f 0.0
Au s 1.0 p 1.0 d 1.0 f 1.0
scf.SO.factor>
#------------------------------------------------------------------------------


This is the input file that I used. Do you see any problem?
Thank you for your help.
メンテ
Re: Controlling SOC strength ( No.5 )
Date: 2018/11/22 23:20
Name: Chi-Cheng

Hi JHong,

I think the problem is due to the "auw_rst".
Every time when you modify the so factor, please delete the auw_rst folder before a new calculation.
OpenMX could misread the restart file and think it is already converged.

Cheers,
Chi-Cheng
メンテ
Re: Controlling SOC strength ( No.6 )
Date: 2018/11/27 15:09
Name: jhong  <sequoia07@postech.ac.kr>

You are right! I restarted the calculation with converged results considering SOC for all atoms.
I removed the every output files from the previous calculations, and now I got the right result for SOC only for Au atom.
Thank you so much! :-)
メンテ

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