[Wannier] About disentanglement keywords in wannier90.win

[fateme sadat Tabatabaei]

On 5/21/16, wannier-request at quantum-espresso.org
<wannier-request at quantum-espresso.org> wrote:
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>    1. About disentanglement keywords in wannier90.win (xiangru kong)
>
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> ----------------------------------------------------------------------
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> Message: 1
> Date: Sat, 21 May 2016 15:15:05 +0800
> From: xiangru kong <kongxru at gmail.com>
> To: wannier at quantum-espresso.org
> Subject: [Wannier] About disentanglement keywords in wannier90.win
> Message-ID:
> 	<CAKn7Z0nb1Yz3uunUsEKoPVx+etpJB38+AFbcJDnDN-=f0biy+Q at mail.gmail.com>
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> Dear all,
>
> I am seeking help for the parameters in wannier90.win.
>
> The 1st one I am confusing is num_wann and num_bands.
> In my opinon now, if i want to focus on all the valence bands only for the
> insulators , the num_wann and num_bands should be the same, for this is the
> isolated bands. However, if I want to include some conduction bands, the
> num_bands should be larger than num_bands for this is the case entangled
> bands. Is it right?
>
> The 2nd is the disentanglement parameters.
>
> The user guide tells us that the disentanglement keywords will be actived
> if  num_wann < num_bands, but if the num_wann=num_bands, does the keywords
> in disentanglement still works well ?
> More I want to know is how to set correctly the dis_win_max(min) and
> dis_froze_max(min)?
>
> the 3th
> how can I make sure the results by wannier90 is good ? Is comparing the
> band structures by wannier90 with DFT a good way?
>
> the 4th
>
> if I have atom orbitals projected like s, px, py, pz, what is the
> difference between projected WFs (num_iter=0) and MLWFs (num_iter=1000 as
> an example)?
>
>
>
>
> All the best to all
> Xiangru Kong
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Hi Xiangru

I'm new in wannier but I hope this will be helpful.

About your 1st and 2nd question:
I understand that when you have some entangled bands in some energies
you should use dis_win_max(min) and dis_froze_max(min) for those
energies.

For your 3th question:There is 4 criterion:
1.In the  output file you should see this:<<< Wannierisation
convergence criteria satisfied >>>
2.WF spread (for final state) should be < 5 angstrom
3. Maximum Im/Re Ratio should be < 10^-4
4. And finally comparing the band structures by wannier90 with DFT

And about your 4th question:There is difference between them in
spreads and centre.you can see their difference by plot wanniers (with
xcrysden)of your system and also in your output. Actually we expect
these difference because the pz or etc are isolated atom's orbitals.

Best
Fateme