From ssg09d at my.fsu.edu  Wed Jul  2 21:26:53 2014
From: ssg09d at my.fsu.edu (Ghosh, Soham Subhra)
Date: Wed, 2 Jul 2014 19:26:53 +0000
Subject: [Wannier] Spin-polarized calculation
Message-ID: <1404329212835.76822@my.fsu.edu>

Dear Wannier90 users,

I am facing the following issues.

1. I am trying to form a few-band model of magnetism in a system that has a few bands crossing the Fermi level.  I understand that orbitals are strongly localized only in insulators. Does it make any sense to use Wannier90 in my system?

2. I have the VASP generated DFT groundstate of a spin-polarized system. I want to target a band which is a up-spin band. The  corresponding down-spin band is displaced by about 0.5 eV and I do not want to include that in my calculation.  However, the 'spinors' tag in Wannier90 expects to find twice as many initial projections. Is there a way to form a Wannier orbital out of an orbital with a spin index, and if there is, how do I specify the initial projection for that band, since projections do not carry a spin-index?

3. Could you kindly tell me why Wannier functions should be mostly real when they are well-localized? I failed to find such a constraint in the derivation of MLWFs.

My apologies if these questions have been already discussed. I did not notice them, but if that is the case, I will be thankful if you point me to the right direction.

Thank you for your time.
Regards,

Soham.



Soham S. Ghosh
Graduate Student
Department of Physics
Florida State University
ssg09d at my.fsu.edu
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From jonathan.yates at materials.ox.ac.uk  Thu Jul  3 12:12:06 2014
From: jonathan.yates at materials.ox.ac.uk (Jonathan Yates)
Date: Thu, 3 Jul 2014 10:12:06 +0000
Subject: [Wannier] Spin-polarized calculation
In-Reply-To: <1404329212835.76822@my.fsu.edu>
References: <1404329212835.76822@my.fsu.edu>
Message-ID: <270E1A64-F617-4899-A968-C241D2E74C65@materials.ox.ac.uk>


On 2 Jul 2014, at 20:26, Ghosh, Soham Subhra <ssg09d at my.fsu.edu> wrote:

> Dear Wannier90 users, 
> 
> I am facing the following issues.
> 
> 1. I am trying to form a few-band model of magnetism in a system that has a few bands crossing the Fermi level.  I understand that orbitals are strongly localized only in insulators. Does it make any sense to use Wannier90 in my system?

yes. Read about wannier functions from entangled bands in
http://journals.aps.org/rmp/abstract/10.1103/RevModPhys.84.1419

> 2. I have the VASP generated DFT groundstate of a spin-polarized system. I want to target a band which is a up-spin band. The  corresponding down-spin band is displaced by about 0.5 eV and I do not want to include that in my calculation.  However, the 'spinors' tag in Wannier90 expects to find twice as many initial projections. Is there a way to form a Wannier orbital out of an orbital with a spin index, and if there is, how do I specify the initial projection for that band, since projections do not carry a spin-index?

Run two separate calculations. One for spin up, the other for spin down.
  See example 8 in the wannier90 tutorials. I know these are for pwscf - but I expect it can be easily adapted to vasp.

> 3. Could you kindly tell me why Wannier functions should be mostly real when they are well-localized? I failed to find such a constraint in the derivation of MLWFs. 

It?s not a constraint. There was an initial conjecture that MLWF should be real - and this has been found empirically to be true. There is a ?proof? of this (for certain conditions) in the papers on exponential localisation of Wannier Functions - see the relevant section (and cited articles therein) of the above RMP article.

 Yours
   Jonathan




-- 
Department of Materials, University of Oxford, Parks Road, Oxford, OX1 3PH, UK
tel: +44 (0)1865 612797                http://users.ox.ac.uk/~oums0549/



From giovanni.pizzi at epfl.ch  Thu Jul 17 16:21:05 2014
From: giovanni.pizzi at epfl.ch (Giovanni Pizzi)
Date: Thu, 17 Jul 2014 16:21:05 +0200
Subject: [Wannier] Mailing list migration
Message-ID: <53C7DBD1.9020106@epfl.ch>

Dear Wannier users,

the listwannier at quantum-espresso.org  has been migrated to a new
server. Archives and all subscribers have been preserved and are
unchanged, so you should not see any difference. No action is
required to be taken by you.

Should you experience any problem in reading or sending email please
reply to this thread including in CC the addresstech at spin.it.

Best Regards,
Giovanni Pizzi

-- 
Giovanni Pizzi
Post-doctoral Research Scientist
EPFL STI IMX THEOS
MXC 340 (B?timent MXC)
Station 12
CH-1015 Lausanne (Switzerland)
Phone: +41 21 69 31124



From szaboa at iis.ee.ethz.ch  Tue Jul 22 16:36:24 2014
From: szaboa at iis.ee.ethz.ch (Aron Szabo)
Date: Tue, 22 Jul 2014 16:36:24 +0200
Subject: [Wannier] wannier90 + vasp parallelism
Message-ID: <53CE76E8.5010708@iis.ee.ethz.ch>

Dear Wannier90 users,

I have noticed that calculating the initial projections for wannier90 
with VASP doesn't speed up with the number of CPU-s used. Is it an 
installation error, or is it only implemented in sequential, like 
wannier90.x itself? And is it the same with other dft-tools (quantum 
espresso, abinit)?

With large supercells it's a very time consuming part, taking days for a 
system with about 500 Wannier functions. I've somewhat circumvented the 
problem by calculating separately the projections on the different atom 
and orbital types, then concatenating (with proper indexing - I can 
share my Matlab script if anyone is interested) the files, but it's 
still very inefficient, because the same overlaps have to be calculated 
first every time (I can't tell VASP that I only need the projections), 
and on supercomputers, where only whole nodes can be reserved, still 
only one cpu will work per node.

So I would appreciate any hints how to deal with large systems 
efficiently, if anyone has any experience with it.

Thanks in advance!

Aron Szabo
(PhD student at ETH Zurich)


From neutrinofrancese at gmail.com  Wed Jul 23 19:15:51 2014
From: neutrinofrancese at gmail.com (Tommaso Francese)
Date: Wed, 23 Jul 2014 17:15:51 -0000
Subject: [Wannier] plot bandstructure
Message-ID: <33E13C23-FFA1-4415-A4CC-2629802DA6BF@gmail.com>

Dear all W. users,
my name is Tommaso Francese and i?m beginner in Wannier90 computational approach. So, it might be a stupid question, but when i try to follow the http://www.wannier.org/cecam07/tutorial_cecam.pdf, i?m able to do the first part (Silicon Valence Bands), until the XcrysDen file generation; but the next (Valence + Conduction State), following the tutorial fails, and the silicon.werr warns me as follow:

 Wannier90: Execution started on 23Jul2014 at 19:08:27 
 Exiting.......
 A bandstructure plot has been requested but there is no kpoint_path block

Can you help me? 

I added the two strings as suggested in the tutorial, but it doesn?t work.

Thanks in advance for every tips,
Best,
Tommaso.
Universit? C? Foscari di Venezia
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From neutrinofrancese at gmail.com  Fri Jul 25 19:23:03 2014
From: neutrinofrancese at gmail.com (Tommaso Francese)
Date: Fri, 25 Jul 2014 17:23:03 -0000
Subject: [Wannier] problem in compiling postw90.x
Message-ID: <495623FE-819D-4E9C-85F8-DAC4B556E434@gmail.com>

Dear all,
i?m working with QE 5.0.2, and i?m trying to use Wannier90 for calculating the DOS and Bands for a Zirconia structure. But when i look for postw90.x code, i?m not able to find it nor to generate it in Wannier90 directory. How can i overcome the problem? i try to follow the readme.install file, but it doesn?t work.

Can anyone help me?

Best,
Tommaso Francese,
Universit? C? Foscari di Venezia