[Pw_forum] k-mesh in pwcond

[Zubaer Hossain]

Thanks for your replies.

I know there's no k-mesh input in the input file for pwcond. Actually, I was
getting different transmission coefficient values with respect to a change
in the k-mesh values for the lead and scat calculations.

I realized that the complex band structures were actually not converged
w.r.t the k-mesh. Seems like pwcond requires quite a dense k-mesh for
convergence, especially for metallic systems. However, now I am getting good
results.

Zubaer



On Mon, Nov 9, 2009 at 4:20 AM, Gabriele Sclauzero <sclauzer at sissa.it>wrote:

>
>
> xirainbow wrote:
> > Dear ：
> > I do not think pwcond can set k-mesh along the transport direction.
> > Instead, you can set k-mesh perpendicular  to the transport direction.
> >
> > The transport device can be period perpendicular to the transport
> direction.
> > However, it is not period along the transport direction
>
> This is right, in the pwcond calculation the Born-von Karman PBCs are
> removed along the
> transport direction, and you need to take care only of the 2D BZ sampling
> in the
> perpendicular directions.
> Anyway, in the preceding pwscf calculation, periodicity is still there in
> all 3
> directions, hence you need a proper k-point sampling also along the
> transport direction,
> especially for the leads, which usually are a bulk periodic unit (hence
> they may not be a
> supercell).
>
> HTH
>
> GS
>
> >
> > On Sat, Nov 7, 2009 at 12:46 AM, Zubaer Hossain <zubaexy at gmail.com
> > <mailto:zubaexy at gmail.com>> wrote:
> >
> >     Dear QE users,
> >
> >     Is there any rule for choosing k-meshes for the lead and the
> >     scattering region along the transport direction?
> >
> >     Thanks in advance,
> >     Zubaer
> >     UIUC
> >
> >
> >
> >
> > --
> > ____________________________________
> > Hui Wang
> > School of physics, Nankai University, Tianjin, China
> >
> >
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> >
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>
> --
>
>
> o ------------------------------------------------ o
> | Gabriele Sclauzero, PhD Student                  |
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> | email: sclauzer at sissa.it                         |
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