From seung43210 at yahoo.com Thu May 6 21:08:44 2010 From: seung43210 at yahoo.com (seunghwan lee) Date: Thu, 6 May 2010 12:08:44 -0700 (PDT) Subject: [Wannier] plotting Wannier orbitals Message-ID: <883705.99470.qm@web50508.mail.re2.yahoo.com> Hi All, I have a question about plotting Wannier orbitals. The question may not make any sense, but is there any way to relate a particular wannier orbital and an energy band? For example, if I want to plot the HOMO and LUMO of a semi-conducting system, is it possible to find these orbitals from the set of MLWO calculated with W90? Thank you for your help. Seunghwan Lee University of North Carolina From a.mostofi at imperial.ac.uk Sat May 8 19:22:12 2010 From: a.mostofi at imperial.ac.uk (Arash Mostofi) Date: Sat, 08 May 2010 18:22:12 +0100 Subject: [Wannier] plotting Wannier orbitals In-Reply-To: <883705.99470.qm@web50508.mail.re2.yahoo.com> References: <883705.99470.qm@web50508.mail.re2.yahoo.com> Message-ID: <4BE59DC4.5050900@imperial.ac.uk> An HTML attachment was scrubbed... URL: From seung43210 at yahoo.com Mon May 10 17:21:43 2010 From: seung43210 at yahoo.com (seunghwan lee) Date: Mon, 10 May 2010 08:21:43 -0700 (PDT) Subject: [Wannier] plotting Wannier orbitals In-Reply-To: <4BE59DC4.5050900@imperial.ac.uk> Message-ID: <645740.31161.qm@web50508.mail.re2.yahoo.com> Dr. Mostofi, Thank you for your kind comments. Is there any way to find this rotation matrix U_mn? I see .anm and .mmn files from W90 output, but not .umn Seunghwan Lee University of North Carolina --- On Sat, 5/8/10, Arash Mostofi wrote: From: Arash Mostofi Subject: Re: [Wannier] plotting Wannier orbitals To: "wannier at quantum-espresso.org" Date: Saturday, May 8, 2010, 1:22 PM Dear Seunghwan, In general, the MLWFs correspond to a transformation of a set of energy bands (determined by the energy windows that one defines). Unless a particular band is isolated from the rest of the bands in the Brillouin zone, which can happen, for example, when you have a very localised defect level, no single particular MLWF will correspond directly to a single particular band. Let us for a moment assume, for simplicity, Gamma-point only sampling of the BZ and that we don't need to do any disentanglement procedure. One may want to know how much "character" of a particular energy eigenstate $\psi_{n}$ is present in a particular MLWF $w_{m}$ (or vice versa). Then one should look at the quantity $|< \psi_{n} | w_{m} >|^2$. If you work it out, this is just $|U_{nm}|^2$ where U is the matrix in Eq. (10) of Marzari & Vanderbilt, Phys Rev B 56, 12847 (1997) [or, alternatively, Eq. (1) of Comput Phys Commun 178, 685 (2008)]. Mathematically, this is just the square of the projection of the eigenstate on the MLWF, and gives a measure of the amount of overlap between them. Hope that helps. Arash -- Dr Arash A Mostofi Lecturer and RCUK Fellow Depts of Materials & Physics Imperial College London London SW7 2AZ, United Kingdom T +44 (0)207 594 8154 F +44 (0)207 594 6757 E a.mostofi at imperial.ac.uk W http://www.cmth.ph.ic.ac.uk/people/a.mostofi seunghwan lee wrote: Hi All, I have a question about plotting Wannier orbitals. The question may not make any sense, but is there any way to relate a particular wannier orbital and an energy band? For example, if I want to plot the HOMO and LUMO of a semi-conducting system, is it possible to find these orbitals from the set of MLWO calculated with W90? Thank you for your help. Seunghwan Lee University of North Carolina _______________________________________________ Wannier mailing list Wannier at quantum-espresso.org http://www.democritos.it/mailman/listinfo/wannier -----Inline Attachment Follows----- _______________________________________________ Wannier mailing list Wannier at quantum-espresso.org http://www.democritos.it/mailman/listinfo/wannier -------------- next part -------------- An HTML attachment was scrubbed... URL: From a.mostofi at imperial.ac.uk Tue May 11 16:36:48 2010 From: a.mostofi at imperial.ac.uk (Arash Mostofi) Date: Tue, 11 May 2010 15:36:48 +0100 Subject: [Wannier] plotting Wannier orbitals In-Reply-To: <645740.31161.qm@web50508.mail.re2.yahoo.com> References: <645740.31161.qm@web50508.mail.re2.yahoo.com> Message-ID: <4BE96B80.6010909@imperial.ac.uk> An HTML attachment was scrubbed... URL: From mazar83 at gmail.com Fri May 21 01:11:52 2010 From: mazar83 at gmail.com (Mark Mazar) Date: Thu, 20 May 2010 18:11:52 -0500 Subject: [Wannier] Projections Message-ID: Hello, I was wondering, is it possible to find wannier functions with bond projections? For example, one of the features of my system is a Ta-C bond. How can I specify the projections in the *.win file in order to capture the bonding behavior between these two atoms? Thank you, -- Mark Mazar PhD Candidate in Materials Science Chemical Engineering and Materials Science University of Minnesota Cell: (732)939-2898 Office: (612)624-3311 From jonathan.yates at materials.ox.ac.uk Mon May 24 00:18:51 2010 From: jonathan.yates at materials.ox.ac.uk (Jonathan Yates) Date: Sun, 23 May 2010 23:18:51 +0100 Subject: [Wannier] Projections In-Reply-To: References: Message-ID: <5658C33F-5001-48CD-85F3-432B389E2324@materials.ox.ac.uk> On 21 May 2010, at 00:11, Mark Mazar wrote: > Hello, > > I was wondering, is it possible to find wannier functions with bond > projections? > > For example, one of the features of my system is a Ta-C bond. How can > I specify the projections in the *.win file in order to capture the > bonding behavior between these two atoms? Mark, I think it is important to realise that the initial projections you specify in the *.win file are simply guesses for the MLWF. Using a good guess will speed up the minimisation - but they should not determine the final form of the MLWF. For a given set of bloch states the MLWF should be well defined (as the set of WF which minimise the quadratic spread). That statement needs a few qualifications to be precise - but it does means that you can't determine the form of the MLWF yourself. If you obtain the MLWF from the set of valence states then they probably will tell you something about the bonding in your material. (eg see the pictures of MLFW in Si and GaAs on wannier.org - also look at the Psi_k article linked from the site). Hope that's of some help. 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 spshu at mail.ustc.edu.cn Mon May 24 14:53:56 2010 From: spshu at mail.ustc.edu.cn (spshu at mail.ustc.edu.cn) Date: Mon, 24 May 2010 20:53:56 +0800 (CST) Subject: [Wannier] Questions encounted in MV97 paper Message-ID: <2418094.1096211274705636887.JavaMail.coremail@mailweb> Dear all, Hello, everyone. We are two senior students in USTC, China. We encounted some problems in derivation of formula(34) in "Maximally localized generalized Wannier functions for composite energy bands", written by N.Marzari and D.Vanderbilt, 1997. In this paper, it says that formula (34) was derived partly using formula(32), however, we could not get rid of the last term "ImlnM_{nn}^{k,b}" originally in formula (32). The second question is that it is difficult for me to obtain formula (26). It seems using Taylor expansion to expand M_{nn}^{k,b} in orders of b. However, I find it not so straightforward. The third question comes from "APPENDIX B: FINITE-DIFFERENCE FORMULAS FOR k-SPACE GRIDS". We want to know where can I find the original theory of finitre-difference that would leads to the "B1 condition". Where did the concept of using weight factor "w_{b}" come from? What is the role it plays in finite-difference for k grids? Thanks a lot. Shipeng Shu, Chen Liao -------------- next part -------------- An HTML attachment was scrubbed... URL: