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planar-averaged electrostatic potential
Date: 2018/10/06 05:07
Name: Po-Hao   <chang.pohao@gmail.com>

Hi all,

I am trying to reproduce the planar-averaged electrostatic potential as
Fig. 1 in Computational Materials Science 151 (2018) 174&#8211;180. but with shorter length.

I have reproduced the result with VASP by selecting LVTOT = .TRUE. in the INCAR and plot out LOCPOT file. The result shows GaAs side has higher potential energy than AlAs.

However when I try to calculate planar-averaged electrostatic potential with the same coordinate as I did in VASP, the energy shift is the opposite to the result mentioned above between GaAs/AlAs (AlAs is higher). I have tried to plot out both v0.cube and vhart.cube. The trend is the same.

Do I misunderstand the definition or what should I do to get the same information regarding the electrostatic potenial shift at the interface?


The following is my input file and please note that the averaged planew in my input file is y-z plane.

Thank you so much for your time.

=========

Species.Number 3
<Definition.of.Atomic.Species
Ga Ga7.0-s3p3d2 Ga_PBE13
As As7.0-s3p3d2 As_PBE13
Al Al7.0-s3p3d2 Al_PBE13
Definition.of.Atomic.Species>

# Atoms

Atoms.UnitVectors.Unit Ang # Ang|AU
<Atoms.UnitVectors
11.296 0 0
0 5.648 0
0 0 5.648
Atoms.UnitVectors>

Atoms.Number 16
Atoms.SpeciesAndCoordinates.Unit Ang # Ang|AU
<Atoms.SpeciesAndCoordinates
1 Ga 0 0 0 6.5 6.5
2 Ga 0 2.824 2.824 6.5 6.5
3 Ga 2.824 2.824 0 6.5 6.5
4 Ga 2.824 0 2.824 6.5 6.5
5 As 4.236 1.412 4.236 7.5 7.5
6 As 1.412 1.412 1.412 7.5 7.5
7 As 1.412 4.236 4.236 7.5 7.5
8 As 4.236 4.236 1.412 7.5 7.5
9 Al 5.648 0 0 1.5 1.5
10 Al 5.648 2.824 2.824 1.5 1.5
11 Al 8.472 2.824 0 1.5 1.5
12 Al 8.472 0 2.824 1.5 1.5
13 As 9.884 1.412 4.236 7.5 7.5
14 As 7.06 1.412 1.412 7.5 7.5
15 As 7.06 4.236 4.236 7.5 7.5
16 As 9.884 4.236 1.412 7.5 7.5
Atoms.SpeciesAndCoordinates>

# SCF or Electronic System

scf.XcType GGA-PBE # LDA|LSDA-CA|LSDA-PW|GGA-PBE
scf.SpinPolarization off # On|Off|NC
scf.SpinOrbit.Coupling off # On|Off, default=off
scf.ElectronicTemperature 300.0 # default=300 (K)
scf.energycutoff 200.0 # default=150 (Ry)
scf.maxIter 80 # default=40
scf.EigenvalueSolver band # DC|GDC|Cluster|Band
scf.Kgrid 2 9 9 # means n1 x n2 x n3
scf.Generation.Kpoint regular # regular|MP
scf.Mixing.Type rmm-diisk # Simple|Rmm-Diis|Gr-Pulay|Kerker|Rmm-Diisk
scf.Init.Mixing.Weight 0.20 # default=0.30
scf.Min.Mixing.Weight 0.001 # default=0.001
scf.Max.Mixing.Weight 0.400 # default=0.40
scf.Mixing.History 10 # default=5
scf.Mixing.StartPulay 7 # default=6
scf.Mixing.EveryPulay 1 # default=6
scf.criterion 1.0e-7 # default=1.0e-6 (Hartree)


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Re: planar-averaged electrostatic potential ( No.1 )
Date: 2018/10/07 01:21
Name: Naoya Yamaguchi

Hi,

According to the manual of VASP:
http://cms.mpi.univie.ac.at/wiki/index.php/LVHAR
you have reproduced it by plotting "the electrostatic contributions only (ionic + Hartree)".

For OpenMX, you should plot the difference between the v0.cube and vxc0.cube (i.e. v0-vxc0). I think the difference corresponds to the electrostatic potential. (c.f.
http://www.openmx-square.org/forum/patio.cgi?mode=view&no=1587
http://www.openmx-square.org/tech_notes/tech1-1_2.pdf
.)

In fact, I confirmed that the trend was reversed by plotting the difference. You can obtain the vxc0.cube (exchange-correlation potential) by adding "level.of.fileout 2" to your input file. (See also
http://www.openmx-square.org/openmx_man3.8/node25.html
.)

Regards,
Naoya Yamaguchi
メンテ
Re: planar-averaged electrostatic potential ( No.2 )
Date: 2018/10/07 05:20
Name: Po-Hao  <chang.pohao@gmail.com>

Dear Naoya,

Thank you so much for your reply.

I followed your suggestion and did v0-vxc0, however the result turns out to be nearly identical as plotting vhart along, somehow vna is almost 0?
In fact I directly compare the cube files, v0-vxc0=vhart

Which means I still don't get the proper trend. AsAs still has higher electrostatic potential.

Do you think there is any technical issue such as some keyword I should specify?
Thanks!

Best regards,
Po-Hao


メンテ
Re: planar-averaged electrostatic potential ( No.3 )
Date: 2018/10/07 13:29
Name: Naoya Yamaguchi

Dear Po-Hao,

I did forget it, and I also added "scf.ProExpn.VNA off" to include the vna term in the v0, could you try it?
And, I leave some URLs related to it for your reference:
http://www.openmx-square.org/openmx_man3.8/node175.html
http://www.openmx-square.org/openmx_man3.8/node24.html
http://www.openmx-square.org/tech_notes/tech15.pdf

Regards,
Naoya Yamaguchi
メンテ
Re: planar-averaged electrostatic potential ( No.4 )
Date: 2018/10/09 05:25
Name: Po-Hao  <chang.pohao@gmail.com>

Dear Naoya,

I have obtained the correct trend as the following
https://imgur.com/a/k48zKyi
Please let me know if it agree with your test.
Thank you so much for your time!

Best regards,
Po-Hao
メンテ
Re: planar-averaged electrostatic potential ( No.5 )
Date: 2018/10/09 12:00
Name: Naoya Yamaguchi

Dear Po-Hao,

Your result appears to be consistent with mine.

Regards,
Naoya Yamaguchi
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