From jun.physics at gmail.com Thu May 7 18:13:02 2009 From: jun.physics at gmail.com (jon) Date: Thu, 7 May 2009 12:13:02 -0400 Subject: [Wannier] hidden actions taken by wannier90? Message-ID: Dear Colleagues, I am working on DMFT applied to iron pnictide and need to obtain the impurity Green function, which is basically the bare Green function being summed over all the momentum points in 1BZ. The tight-binding hoppings are extracted from fitting to a band structure calculated through MLWS using wannier90. These hoppings have cubic symmetry(on 2D plane though). The impurity Green function turns out to be diagonal in the orbital indices. This is not generally the case unless the wannier states have been taken further actions to form cubic harmonics(I am not an LDA expert, thus please correct me if I am wrong here) before output. However, the tutorial or introduction does not explicitly mention this action and I am thus confused. Thanks, Sincerely, Jon -------------- next part -------------- An HTML attachment was scrubbed... URL: From marzari at MIT.EDU Thu May 7 18:30:40 2009 From: marzari at MIT.EDU (Nicola Marzari) Date: Thu, 07 May 2009 12:30:40 -0400 Subject: [Wannier] hidden actions taken by wannier90? In-Reply-To: <4A030C9E.3070601@mit.edu> References: <4A030C9E.3070601@mit.edu> Message-ID: <4A030CB0.7090005@mit.edu> Nicola Marzari wrote: > > > Dear Jon, > > > have a look at the Posternak...Marzari 2002 PRB. I presume that > that refers to your problem - you need to diagonalize in the subspace of > localized orbitals to recover symmetries that are not built in in > the second-moment minimization. > > Let us know if that is the problem that affects you, > > nicola > > > jon wrote: >> Dear Colleagues, >> >> I am working on DMFT applied to iron pnictide and need to obtain the >> impurity Green function, which is basically the bare Green function >> being summed over all the momentum points in 1BZ. The tight-binding >> hoppings are extracted from fitting to a band structure calculated >> through MLWS using wannier90. These hoppings have cubic symmetry(on 2D >> plane though). The impurity Green function turns out to be diagonal in >> the orbital indices. This is not generally the case unless the wannier >> states have been taken further actions to form cubic harmonics(I am >> not an LDA expert, thus please correct me if I am wrong here) before >> output. However, the tutorial or introduction does not explicitly >> mention this action and I am thus confused. >> >> Thanks, >> >> Sincerely, >> Jon >> >> >> ------------------------------------------------------------------------ >> >> _______________________________________________ >> Wannier mailing list >> Wannier at quantum-espresso.org >> http://www.democritos.it/mailman/listinfo/wannier > > -- --------------------------------------------------------------------- Prof Nicola Marzari Department of Materials Science and Engineering 13-5066 MIT 77 Massachusetts Avenue Cambridge MA 02139-4307 USA tel 617.4522758 fax 2586534 marzari at mit.edu http://quasiamore.mit.edu From invite+kr4mqregyekn at facebookmail.com Thu May 7 22:17:25 2009 From: invite+kr4mqregyekn at facebookmail.com (Vivek Ranjan) Date: Thu, 7 May 2009 13:17:25 -0700 Subject: [Wannier] Check out my photos on Facebook Message-ID: <55a129ab62b29c708e0fdeed509c6312@localhost.localdomain> Hi Wannier, I invited you to join Facebook a while back and wanted to remind you that once you join, we'll be able to connect online, share photos, organize groups and events, and more. Thanks, Vivek To sign up for Facebook, follow the link below: http://www.facebook.com/p.php?i=821428269&k=S5EY2WS2WW6M5BD1QB64RPUSVTC&r wannier at quantum-espresso.org was invited to join Facebook by Vivek Ranjan. If you do not wish to receive this type of email from Facebook in the future, please click on the link below to unsubscribe. http://www.facebook.com/o.php?k=087c32&u=100000013440510&mid=6d3f03G5af3114755feG0G8 Facebook's offices are located at 156 University Ave., Palo Alto, CA 94301. -------------- next part -------------- An HTML attachment was scrubbed... URL: From jun.physics at gmail.com Fri May 8 20:30:25 2009 From: jun.physics at gmail.com (jon) Date: Fri, 8 May 2009 14:30:25 -0400 Subject: [Wannier] hidden actions taken by wannier90? In-Reply-To: <4A030CB0.7090005@mit.edu> References: <4A030C9E.3070601@mit.edu> <4A030CB0.7090005@mit.edu> Message-ID: Dear Prof. Marzari, Let me see whether I interpret your paper right. Basically, for a crystal with lower symmetry, MLWS could still have arbitrariness in choosing its form. Thus, introducing a new criterion by minimizing could further reduce the arbitrariness, but not fully remove it. So, is this what you mean by "to recover symmetries that are not built in in the second-moment minimization"? I guess the then relevant question related to my problem would be: is minimization on implemented in the wannier90 code? To help understand the issue better, I would ask two more questions: is this minimization equivalent to attempts to build in lattice symmetry further, or in other words, is the removal of arbitrariness equivalent in some sense to restoration of crystal symmetry for the wannier states? Is there logic behind if this equivalence holds? Thanks for your kind help, Sincerely, Jon On Thu, May 7, 2009 at 12:30 PM, Nicola Marzari wrote: > Nicola Marzari wrote: > >> >> >> Dear Jon, >> >> >> have a look at the Posternak...Marzari 2002 PRB. I presume that >> that refers to your problem - you need to diagonalize in the subspace of >> localized orbitals to recover symmetries that are not built in in >> the second-moment minimization. >> >> Let us know if that is the problem that affects you, >> >> nicola >> >> >> jon wrote: >> >>> Dear Colleagues, >>> >>> I am working on DMFT applied to iron pnictide and need to obtain the >>> impurity Green function, which is basically the bare Green function being >>> summed over all the momentum points in 1BZ. The tight-binding hoppings are >>> extracted from fitting to a band structure calculated through MLWS using >>> wannier90. These hoppings have cubic symmetry(on 2D plane though). The >>> impurity Green function turns out to be diagonal in the orbital indices. >>> This is not generally the case unless the wannier states have been taken >>> further actions to form cubic harmonics(I am not an LDA expert, thus please >>> correct me if I am wrong here) before output. However, the tutorial or >>> introduction does not explicitly mention this action and I am thus confused. >>> >>> Thanks, >>> >>> Sincerely, >>> Jon >>> >>> >>> ------------------------------------------------------------------------ >>> >>> _______________________________________________ >>> Wannier mailing list >>> Wannier at quantum-espresso.org >>> http://www.democritos.it/mailman/listinfo/wannier >>> >> >> >> > > -- > --------------------------------------------------------------------- > Prof Nicola Marzari Department of Materials Science and Engineering > 13-5066 MIT 77 Massachusetts Avenue Cambridge MA 02139-4307 USA > tel 617.4522758 fax 2586534 marzari at mit.edu http://quasiamore.mit.edu > -------------- next part -------------- An HTML attachment was scrubbed... URL: From marzari at MIT.EDU Fri May 8 23:36:30 2009 From: marzari at MIT.EDU (Nicola Marzari) Date: Fri, 08 May 2009 17:36:30 -0400 Subject: [Wannier] hidden actions taken by wannier90? In-Reply-To: References: <4A030C9E.3070601@mit.edu> <4A030CB0.7090005@mit.edu> Message-ID: <4A04A5DE.50806@mit.edu> Hi Jon, (as usual, do sign your emails, so we know a bit more about you). The problem is that the Wannier functions you obtain from minimization of the spread can be invariant (mathematically, or just numerically) with respect to certain unitary transformations - so the WFs do not have the symmetry that you expect. For this reason, we suggested in the 2002 PRB to perfrom an additional transformation (that would not change the spread) that would remove this degeneracy - for the case of d orbitals studied there is was the diagonalization of . The choice of what you diagonalize depends on the symmetry you want to recover, and you might need to construct by hand (working on the code) the additional matrix elements that are needed. I never tried it, but if you were to give trial projections that already had the riht symmetry, and the right shape, maybe the code would not move away from that (even if there would be nothing opposing it - so just numerical build-up could slowly shift you away). nicola jon wrote: > Dear Prof. Marzari, > > Let me see whether I interpret your paper right. Basically, for a > crystal with lower symmetry, MLWS could still have arbitrariness in > choosing its form. Thus, introducing a new criterion by minimizing > could further reduce the arbitrariness, but not fully remove it. So, is > this what you mean by "to recover symmetries that are not built in in > the second-moment minimization"? > > I guess the then relevant question related to my problem would be: is > minimization on implemented in the wannier90 code? To help > understand the issue better, I would ask two more questions: is this > minimization equivalent to attempts to build in lattice symmetry > further, or in other words, is the removal of arbitrariness equivalent > in some sense to restoration of crystal symmetry for the wannier states? > Is there logic behind if this equivalence holds? > > Thanks for your kind help, > > Sincerely, > Jon > > On Thu, May 7, 2009 at 12:30 PM, Nicola Marzari > wrote: > > Nicola Marzari wrote: > > > > Dear Jon, > > > have a look at the Posternak...Marzari 2002 PRB. I presume that > that refers to your problem - you need to diagonalize in the > subspace of > localized orbitals to recover symmetries that are not built in in > the second-moment minimization. > > Let us know if that is the problem that affects you, > > nicola > > > jon wrote: > > Dear Colleagues, > > I am working on DMFT applied to iron pnictide and need to > obtain the impurity Green function, which is basically the > bare Green function being summed over all the momentum > points in 1BZ. The tight-binding hoppings are extracted from > fitting to a band structure calculated through MLWS using > wannier90. These hoppings have cubic symmetry(on 2D plane > though). The impurity Green function turns out to be > diagonal in the orbital indices. This is not generally the > case unless the wannier states have been taken further > actions to form cubic harmonics(I am not an LDA expert, thus > please correct me if I am wrong here) before output. > However, the tutorial or introduction does not explicitly > mention this action and I am thus confused. > > Thanks, > > Sincerely, > Jon > > > ------------------------------------------------------------------------ > > _______________________________________________ > Wannier mailing list > Wannier at quantum-espresso.org > > http://www.democritos.it/mailman/listinfo/wannier > > > > > > -- > --------------------------------------------------------------------- > Prof Nicola Marzari Department of Materials Science and Engineering > 13-5066 MIT 77 Massachusetts Avenue Cambridge MA 02139-4307 USA > tel 617.4522758 fax 2586534 marzari at mit.edu > http://quasiamore.mit.edu > > -- --------------------------------------------------------------------- Prof Nicola Marzari Department of Materials Science and Engineering 13-5066 MIT 77 Massachusetts Avenue Cambridge MA 02139-4307 USA tel 617.4522758 fax 2586534 marzari at mit.edu http://quasiamore.mit.edu From jun.physics at gmail.com Fri May 8 23:52:07 2009 From: jun.physics at gmail.com (jon) Date: Fri, 8 May 2009 17:52:07 -0400 Subject: [Wannier] hidden actions taken by wannier90? In-Reply-To: <4A04A5DE.50806@mit.edu> References: <4A030C9E.3070601@mit.edu> <4A030CB0.7090005@mit.edu> <4A04A5DE.50806@mit.edu> Message-ID: Thanks, Nicola, So, the code does not implement the additional operation as a default option then? Then, I might have to ask this way. If you know of the iron pnictide, do you expect the resulting MLWS has the crystal symmetry? Under what condition would the MLWS gain the symmetry of the original lattice? or, maybe the answer is a short no, it is just not guaranteed since mathematically a unitary transformation would not change the nature of the problem, as you mentioned just now. Sincerely, Jon On Fri, May 8, 2009 at 5:36 PM, Nicola Marzari wrote: > > > Hi Jon, > > > (as usual, do sign your emails, so we know a bit more about you). > > The problem is that the Wannier functions you obtain from minimization > of the spread can be invariant (mathematically, or just numerically) > with respect to certain unitary transformations - so the WFs do not > have the symmetry that you expect. > > For this reason, we suggested in the 2002 PRB to perfrom an additional > transformation (that would not change the spread) that would remove this > degeneracy - for the case of d orbitals studied there is was the > diagonalization of . > > The choice of what you diagonalize depends on the symmetry you want to > recover, and you might need to construct by hand (working on the code) > the additional matrix elements that are needed. > > I never tried it, but if you were to give trial projections that > already had the riht symmetry, and the right shape, maybe the code > would not move away from that (even if there would be nothing > opposing it - so just numerical build-up could slowly shift you > away). > > nicola > > > > jon wrote: > >> Dear Prof. Marzari, >> >> Let me see whether I interpret your paper right. Basically, for a crystal >> with lower symmetry, MLWS could still have arbitrariness in choosing its >> form. Thus, introducing a new criterion by minimizing could further >> reduce the arbitrariness, but not fully remove it. So, is this what you mean >> by "to recover symmetries that are not built in in the second-moment >> minimization"? >> >> I guess the then relevant question related to my problem would be: is >> minimization on implemented in the wannier90 code? To help understand >> the issue better, I would ask two more questions: is this minimization >> equivalent to attempts to build in lattice symmetry further, or in other >> words, is the removal of arbitrariness equivalent in some sense to >> restoration of crystal symmetry for the wannier states? Is there logic >> behind if this equivalence holds? >> >> Thanks for your kind help, >> >> Sincerely, >> Jon >> >> On Thu, May 7, 2009 at 12:30 PM, Nicola Marzari > marzari at mit.edu>> wrote: >> >> Nicola Marzari wrote: >> >> >> >> Dear Jon, >> >> >> have a look at the Posternak...Marzari 2002 PRB. I presume that >> that refers to your problem - you need to diagonalize in the >> subspace of >> localized orbitals to recover symmetries that are not built in in >> the second-moment minimization. >> >> Let us know if that is the problem that affects you, >> >> nicola >> >> >> jon wrote: >> >> Dear Colleagues, >> >> I am working on DMFT applied to iron pnictide and need to >> obtain the impurity Green function, which is basically the >> bare Green function being summed over all the momentum >> points in 1BZ. The tight-binding hoppings are extracted from >> fitting to a band structure calculated through MLWS using >> wannier90. These hoppings have cubic symmetry(on 2D plane >> though). The impurity Green function turns out to be >> diagonal in the orbital indices. This is not generally the >> case unless the wannier states have been taken further >> actions to form cubic harmonics(I am not an LDA expert, thus >> please correct me if I am wrong here) before output. >> However, the tutorial or introduction does not explicitly >> mention this action and I am thus confused. >> >> Thanks, >> >> Sincerely, >> Jon >> >> >> >> ------------------------------------------------------------------------ >> >> _______________________________________________ >> Wannier mailing list >> Wannier at quantum-espresso.org >> >> http://www.democritos.it/mailman/listinfo/wannier >> >> >> >> >> >> -- >> --------------------------------------------------------------------- >> Prof Nicola Marzari Department of Materials Science and Engineering >> 13-5066 MIT 77 Massachusetts Avenue Cambridge MA 02139-4307 USA >> tel 617.4522758 fax 2586534 marzari at mit.edu >> http://quasiamore.mit.edu >> >> >> > > -- > --------------------------------------------------------------------- > Prof Nicola Marzari Department of Materials Science and Engineering > 13-5066 MIT 77 Massachusetts Avenue Cambridge MA 02139-4307 USA > tel 617.4522758 fax 2586534 marzari at mit.edu http://quasiamore.mit.edu > -- department of physics and astronomy louisiana state univeristy -------------- next part -------------- An HTML attachment was scrubbed... URL: From jonathan.yates at materials.ox.ac.uk Sat May 9 12:23:34 2009 From: jonathan.yates at materials.ox.ac.uk (Jonathan Yates) Date: Sat, 9 May 2009 11:23:34 +0100 Subject: [Wannier] hidden actions taken by wannier90? In-Reply-To: References: <4A030C9E.3070601@mit.edu> <4A030CB0.7090005@mit.edu> <4A04A5DE.50806@mit.edu> Message-ID: Jon, Just to be clear about the practical part of your question: On 8 May 2009, at 22:52, jon wrote: > So, the code does not implement the additional operation as a > default option then? Correct. Wannier90 minimises the total quadratic spread of the set of Wannier orbitals. Nothing else is imposed. So that people could reproduce the 2002PRB we added a flag write_r2mn which, if true, will write the elements of to a file. One could then diagonalise the appropriate part of this (by hand), and obtain the additional unitary rotation. (of course, this could be programmed within the main code) Yours Jonathan -- Department of Materials, University of Oxford, Parks Road, Oxford, OX1 3PH, UK tel: +44 (0)1865 283225 http://users.ox.ac.uk/~oums0549/