[QE-developers] Hybrid functional band structure calculation

[Dr. Thomas Brumme]

Dear Shuyang,

Why don't people use the searchable mail archive? This kind of question was
already asked several times and Lorenzo Paulatto recently gave a quite
extensive answer, which you can find under the following link and which I
cite at the end of the mail:

https://www.mail-archive.com/users@lists.quantum-espresso.org/msg33817.html

Please search before you ask!
I can furthermore add to Lorenzos answer that you can also get the band
structure by interpolating the E(k) dispersion on the regular grid like it
is done in the BoltzTraP code:

https://www.imc.tuwien.ac.at//forschungsbereich_theoretische_chemie/forschungsgruppen/prof_dr_gkh_madsen_theoretical_materials_chemistry/boltztrap/
https://www.sciencedirect.com/science/article/pii/S0010465506001305

Regards

Thomas

the mail:

Hello,
The problem is quite fundamental, because in order to get the Fock  
operator at a certain k-point you need the wavefunctions on a grid  
that is commensurate with it, this can only be done self-consistently.

However, there are a few things you can do.

1. I think you can add k-points to the scf calculation with weight  
zero, this is boring (you'll have to specify he grid and the path by  
hand) and very computationally expensive.

2. you can interpolate the Fock operator, this should be possible if  
it is expressed om a basis of localized wavrfunctions. There is some  
development in this direction, but I don't know if it has been  
implemented already by someone.

3. You could interpolate the wavefunctions, from Wannier functions.  
This is probably impossible in practice.

4. You can interpolate the Hamiltonian, passing through a Wannier  
basis representation. This is possible, I have done it, and I've put  
an example in the git developement branch  
(PP/examples/W90_open_grid_example/). But you need to know, or learn,  
how to use Wannier90 (which is a useful skill regardless), and to use  
the developement version of qe.


Zitat von Shuyang Yang <shuyang1 at andrew.cmu.edu>:

> Hi,  All,
>
> After I run the scf calculation with PBE0, I want to use  
> calculation=‘bands’ with PBE0, but this message occurs:
>
> Error in routine setup (1):
>      hybrid XC not allowed in non-scf calculations
>
> Does any one know how to fix it ? Or how can I calculate the hybrid  
> function band structure in the right way.
> My qe version is 6.1
>
> Best,
> Shuyang,
> Carnegie Mellon University
> _______________________________________________
> developers mailing list
> developers at lists.quantum-espresso.org
> https://lists.quantum-espresso.org/mailman/listinfo/developers

-- 
Dr. rer. nat. Thomas Brumme
Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry
Leipzig University
Phillipp-Rosenthal-Strasse 31
04103 Leipzig

Tel:  +49 (0)341 97 36456

email: thomas.brumme at uni-leipzig.de