Thank you very much professor. Normally I start with,

(1) default outer energy window (taken from DFT by W90 code),
(2) Efermi+-1 inner energy window
(3) projection of those states which have maximum DOS at Fermi level
(4) SCF like k-points mesh or 12x12x12 generated by kmesh.pl

Then iterate over different inner energy window to match DFT and interpolated band structure. Is there any smarter way to do this?

with many thanks and best regards
Soumyadeep

On 09-03-2020 20:01, Nicola Marzari wrote:
Looks good to me, and in outer you want the wannier interpolated to be smooth.

                        nicola


On 09/03/2020 15:04, Soumyadeep wrote:
Thank you very much professor Marzari for an elaborate description. But for MLWF, I check only these

(1) DFT and wannier interpolated band structure must match in inner energy window
(2) final spread is low
(3) Img[h^R_ij] ~ 0

Is there any other factor I need to check?

Normally I work on Fe-based superconducting materials which is metallic in nature and also have entangled bands.

with best regards
Soumyadeep


On 09-03-2020 16:54, Nicola Marzari wrote:
Hi Soumyadeep,

plenty of literature on this, but some cases are discussed in Sec III of
https://arxiv.org/abs/1909.00433

In a nutshell: for non-magnetic insulators, the localization
functional on the occupied bands seems to have one (or multiple, by
symmetries - think benzene) well defined global minimum - all others
correspond to messed-up phase factors, give rise to meaningless WFs,
and those are not real (i.e. they have an imaginary components). I
cannot discount though that e.g. during a mol. dyn. simulations one
could find discontinuous jumps in the MLWFs centers from one timestep
to another.

For non-magnetic systems where you disentangle also the empty bands,
you can have more subtle, complex effects (see discussion above). In
that respect, it also dependes if we call maximally localized the
global minimum only, or also other local minima where WFs are real and
look meaningful.

For magnetic system, we have less case studies, and in general there
are already multiple local minima of the KS-DFT functional.

If anyone has experiences something different, welcome to mention it here.

                nicola


On 09/03/2020 06:21, Soumyadeep wrote:
Dear All,

   I have a query, is Maximally localized Wannier functions are unique set of functions? I mean for a particular system only one set of MLWF is possible or it can be many set depending on other factors?

   Waiting eagerly for your reply.

with many thanks and best regards
Soumyadeep
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Soumyadeep Ghosh,
Senior Research Fellow,
Homi Bhabha National Institute (HBNI),
Raja Ramanna Centre for Advanced Technology, Indore, India-452013
Mob: (+91)9424664553
User Lab: 0731244-2580
Email: [email protected], [email protected]
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