The ABINIT Users Mailing List ( CLOSED )

[Anurag Chaudhry <anuragchaudhry@yahoo.co.uk>]

Hi,

Thanks for replying to the posting.

I am still not very clear on how to run a GW calculation to get the indirect gap correctly for say Silicon.

can someone please tell the steps to run such a calculation.

regards,
Anurag

---

From: Fabien Bruneval <fabien.bruneval@cea.fr>
To: forum@abinit.org
Sent: Thursday, 2 July, 2009 23:52:03
Subject: Re: [abinit-forum] GW calculations

Hi!

The first GW tutorial is a bit misleading indeed. You can and you must run GW calculation for sets of k-points.
The only constrain is that the k-point set is a regular grid.
You can take a look at the second GW tutorial, which is more realistic.

Regards,

Fabien




Anurag Chaudhry wrote:
> Hi,
>
> I am new to GW calculations though I have used ABINIT earlier.  I saw the tutorial on GW approximation and have few questions.
>
> If I understand correctly, then it is only possible to run a GW calculation for a single k-point.  For example, GW calculations for Silicon in the tutorial are shown for Gamma point.  Since the bandgap of Si is ~1.2eV (as I know) and it is an in-direct bandgap material is there a way to get this right ?  The calculations at the end of tutorial show that the LDA gap at the Gamma point is ~253eV and GW correction adds about 0.63eV to this value.
>
> I have to run calculations to determine bandgaps of certain Bi and Pb semiconductors with beyond LDA/GGA methods.  This is how I started looking at GW but I am not sure if this is the right approach.
>
> Any comments and suggestions are welcome.
>
> regards,
> Anurag
>