[Pw_forum] Si Bandstructure in HSE: Wannier90

[DHIRENDRA VAIDYA]

I want to check implementation of Hybrid functional in QE, to see how it
works well (on Silicon). Choice of Silicon is obvious because of its
extensive study. At present I did not find any method to obtain the
Bandstructure using Hybrid functionals in PWSCF. A dense grid is
computationally expensive and so I want to find another method to obtain
the Bandstructure using Hybrid Functionals. I want to extend the method for
other Gr IV materials like Ge, Sn and alloys. Let me repeat my simulation
scheme,
1. Do scf calculations using GGA.
2. Do scf calculations using HSE. restart_mode='restart', modify K_POINTS
using a K mesh generated using perl script given in Wannier90
3. use Wannier90 as Postprocessing tool and plot the bandstructure.

This method ends up in to lot of errors in selecting the K points and q
mesh for HSE, but from my forum research, I find that this is only method
available.
Any comments? Please suggest if another method is possible.

On Sun, May 17, 2015 at 6:41 PM, nicvok <nicvok at freenet.de> wrote:

> Dear Dhirendra,
>
> which information do you need exactly for silicon. Only the bandstructure
> which is near the experiment?
> Sure, due to the connection of the hamiltonian/Eigenvalues to charge
> density AND wavefunctions a nscf calculation won’t do the trick, but I am
> pretty sure
> that a „dense“ scf-calculation with paths you need for a bandstructure
> will work out. Otherwise maybe even a simple sp3s*
> tight-binding calculation will be enough for your needs - it works quite
> well for Si.
> I have no idea, what you did with the Wannier functions - usually you need
> proper Eigenvalues (in your case the HSE bandstructure)
> where you map onto. Building a Wannier-based Hamiltonian from LDA/GGA
> Eigenvalues won’t give a leap forward.
>
> bests
> Nicki
>
> --------------------------------------------------------
> Nicki Frank Hinsche, Dr. rer. nat.
> Institute of physics - Theoretical physics,
> Martin-Luther-University Halle-Wittenberg,
> Von-Seckendorff-Platz 1, Room 1.07
> D-06120 Halle/Saale, Germany
> Tel.: ++49 345 5525460
> --------------------------------------------------------
>
> Am 17.05.2015 um 12:00 schrieb pw_forum-request at pwscf.org:
>
> Date: Sun, 17 May 2015 05:29:29 +0530
> From: DHIRENDRA VAIDYA <dhirendra22121987 at gmail.com>
> Subject: [Pw_forum] Si Bandstructure in HSE: Wannier90
> To: PWSCF Forum <pw_forum at pwscf.org>
> Message-ID:
> <CAJLtapV=mb6tdgfej9o8PKoJ0FZXmO7pXjjh8aUWYASz-K7mOA at mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
>
>
> Hi,
>
> So far PWSCF provides little help in Silicon bandstructure using HSE. But
> from PWSCF forum it is clear to me now that in HSE nscf calculations cannot
> be performed. The VASP method of zero weights on KPOINTS doesn't work due
> to an error ' k+q is not an s*k'. I had some success in using Wannier90 as
> post processing tool. Is it the right way to obtain the bandstructure of
> Si?
>
> --
> --
> Dhirendra
>
>
>
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-- 
--
Dhirendra
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