[Wannier] which band should be wannierise for transport properties?

[Jesse Vaitkus]

This is a rather fundamental question, and for the most part depends on
what you look to describe.

Typically, with these sorts of calculations only a subset of bands are
chosen via the following decisions:
First, one decides an energy range they wish to model (typically about the
Fermi energy) and they then include the bands in that energy window.
Secondly one decides how many Wannier functions they'd like. A maximum of
one per band will give the best results, fewer and you lead to an
approximation.
Thirdly, even if you have enough Wannier functions for your window, you
need to see if any of the bands are 'entangled' by asking the question "Do
they overlap with bands outside the calculation window?".
If they are entangled, you should either increase your window until they or
not OR select a frozen window which determines which band structure you
want to 'lock in'. This can be a tricky problem.

For initial projections, chemical intuition is required, if you have one
Wannier site per band they will typically be bond centred, so you can use
that as a starting point but the specifics are different for each system.

I suggest you have a much larger look at your system, decide what it is
that you are trying to model in terms of bands, energies, physics and the
answer should hopefully come to you naturally.

Cheers,
Jesse Vaitkus

On 17 May 2016 at 13:36, fateme sadat Tabatabaei <tabatabaei69 at gmail.com>
wrote:

> Hi everyone
> I'm investigating quantum transport properties.
> I have a question: which bands should be wannierise?
> valence? conduction? both of them? or all bands?
> _______________________________________________
> Wannier mailing list
> Wannier at quantum-espresso.org
> http://mailman.qe-forge.org/cgi-bin/mailman/listinfo/wannier
>



-- 

————————————————————————————————
Mr. Jesse Vaitkus MAIP
BAppSc(Phys) Hons, BAppSc(Nano)

PhD candidate
Room 14.6.02

Chemical and Quantum Physics
School of Applied Sciences
RMIT University
Victoria 3001
Australia

jesse.vaitkus at rmit.edu.au
————————————————————————————————
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/wannier/attachments/20160517/c3b2f9fd/attachment.html>