QuantumATK Forum

QuantumATK => General Questions and Answers => Topic started by: Dipankar Saha on July 4, 2014, 16:13

Title: SOLDA/ spin-orbit
Post by: Dipankar Saha on July 4, 2014, 16:13

What functional should we use for SOLDA....?... PW? /
How to see a distinguished split in VBM (I wanted to mean..what are the the steps) ...??

Title: Re: SOLDA/ spin-orbit
Post by: Anders Blom on July 4, 2014, 17:33

That's up to you. Why not try a few different ones and see if the results differ a lot?
I didn't understand the part about seeing the split.

Title: Re: SOLDA/ spin-orbit
Post by: Dipankar Saha on July 6, 2014, 09:22

How to see the effect of S-O-C on band struct. ...?

Title: Re: SOLDA/ spin-orbit
Post by: Umberto Martinez on July 7, 2014, 15:33

You will see for example some band splits for bands which would be degenerate if you do not consider SO.
the SO splitting depends on the particular system.

see for example InAs http://www.ioffe.rssi.ru/SVA/NSM/Semicond/InAs/bandstr.html#Basic

Title: Re: SOLDA/ spin-orbit
Post by: Dipankar Saha on July 7, 2014, 16:57

Yeah..that's true.../ But I wanted to ask... how can I include S-O-C in my band structure dynamics? / Say for MoS₂...at same k, how can I get the diff. in band structure dynamics(one with spin degeneracy..one with S-O-C)?

Title: Re: SOLDA/ spin-orbit
Post by: Dipankar Saha on July 7, 2014, 17:11

Example:-
It is something like the fig. 2 ...of the following reference...
http://journals.aps.org/prb/pdf/10.1103/PhysRevB.84.153402

Title: Re: SOLDA/ spin-orbit
Post by: Umberto Martinez on July 14, 2014, 10:53

Here you can get a glimpse of SOC which will be available in ATK 2014:
http://quantumwise.com/publications/tutorials/mini-tutorials/253#h6-spin-orbit-coupling

still not sure I got your question but I hope this helps.

Title: Re: SOLDA/ spin-orbit
Post by: Dipankar Saha on July 15, 2014, 11:24

Umberto Martinez,

Excellent.... Thanks a lot for the tutorial.... May be this is not what I was exactly looking for...But still this will help a lot.... :) / Thanks... :)

Title: Re: SOLDA/ spin-orbit
Post by: Dipankar Saha on July 15, 2014, 17:28

Meaning of this Error....??

____________

Traceback (most recent call last):
  File "./zipdir/NL/Calculators/BulkCalculatorInterface.py", line 243, in _update
  File "./zipdir/NL/ComputerScienceUtilities/Timer.py", line 45, in __call__
  File "./zipdir/NL/Calculators/BulkCalculatorInterface.py", line 243, in <lambda>
  File "./zipdir/NL/Calculators/CommonBuilder/BulkBuilder.py", line 128, in createDensityMatrixCalculator
  File "./zipdir/NL/Calculators/LCAOCalculator/Builders/AbstractLCAOBuilder.py", line 111, in createMatrixCalculator
  File "./zipdir/NL/Calculators/PseudoPotentials/NormConservingPseudoPotential.py", line 132, in load
  File "./zipdir/NL/Calculators/PseudoPotentials/NormConservingPseudoPotential.py", line 240, in _loadVPS
NLIOError: Projection energies of non-local OpenMX projectors are not equal.
Traceback (most recent call last):
  File "/tmp/5888504749009959.py", line 86, in <module>
    bands_above_fermi_level=All
  File "./zipdir/NL/Analysis/Bandstructure.py", line 194, in __init__
  File "./zipdir/NL/Analysis/Bandstructure.py", line 496, in calculateBandstructure
AttributeError: 'NoneType' object has no attribute 'fermiDistribution'

Title: Re: SOLDA/ spin-orbit
Post by: Dipankar Saha on July 15, 2014, 17:36

Umberto Martinez,

For LSDA-PZ.......  may be the basis set that had been chosen was inappropriate ...
Can u please check the attachment...

Regards_
Dipankar

Title: Re: SOLDA/ spin-orbit
Post by: Dipankar Saha on July 15, 2014, 21:33

Further to add.....

The above mentioned prob. can be avoided if I use... LSDA-PZ exchng correlation... with a basis set Tier 0 ... having FHI or HGH [Z=6] LDA.PZ as the pseudopotential of the individual elements.....

But, then the effect of S-O-C (done with SOLDA) on band structure is simply nothing....
[As it has correctly been mentioned in the tutorial also__ "In order to sun a SO calculation later on you need fully relativistic pseudopotentials..."]

Again, SGGA-PBE exchng correlation... with OMX pseudopotentials... giving the same error message as it has been mentioned in my earlier post...

What is the way out...?? (because as per the literature[ http://journals.aps.org/prb/pdf/10.1103/PhysRevB.84.153402 ] I should get some effect of S-O-C on band strcuts. of TMDs...)

Title: Re: SOLDA/ spin-orbit
Post by: Umberto Martinez on July 16, 2014, 10:00

Yes, you are absolutely right. you need the proper pseudopotentials.

I do not understand the error (cannot reproduce it) but be aware that the SOC is quite a new feature in ATK 2014 which is still a preview version, i.e. minor fixes are still in progress.
You may have found a bug, congratulations!

that said, try the very last one ATK 2014.a4 version available at the download page http://quantumwise.com/products/download

By using this version I get a valence band splitting of 142 meV in agreement with your reference, check attachments.

Please, let us know if your problem persist.
If so, please send all the information you have about your machine/installation/scripts/... to help us solve the issue.

Title: Re: SOLDA/ spin-orbit
Post by: Dipankar Saha on July 16, 2014, 13:19

Umberto Martinez,

Thank you once again.... Let me install ATK 2014.a4  and try this....
I will let you know... :)

Regards__
Dipankar