From j.wohlwend at live.com Mon Aug 5 20:31:15 2013 From: j.wohlwend at live.com (Jennifer Wohlwend) Date: Mon, 5 Aug 2013 14:31:15 -0400 Subject: [Wannier] large Im/Re Message-ID: Dear all, I'm using WANNIER90 (Release: 1.1.1) as a library with pwscf and epw.x for Copper. Although I'm using the same starting projections as the example (I've also tried starting with 'random') with 15 bands (7 WFs) and an 8x8x8 k-point mesh the Im/Re ratio is still quite high especially for the interstitial WF (6 and 7). The spread is also somewhat larger than the example found here: http://www.tcm.phy.cam.ac.uk/~jry20/wannier/copper.html. The band structure reproduces well and the visualization of the (1-5) WF look like 3dx2-y2 , 3dz2 , 3dxy, 3dxz, and 3dyz orbitals whereas the 6 & 7 WF look like distorted s orbitals. I've included guiding_centres = T as well but I'm still getting imaginary WF. I have included the center/spread data, Im/Re ratio data, the .win file created by epw.x as well as the pwscf.in file for my system. Thank you in advance for any suggestions on how to remedy this situation. Final State WF centre and spread 1 ( 0.000000, 0.000000, 0.000000 ) 0.47410645 WF centre and spread 2 ( 0.000000, 0.000000, 0.000000 ) 0.45976002 WF centre and spread 3 ( 0.000000, 0.000000, 0.000000 ) 0.45976002 WF centre and spread 4 ( 0.000000, 0.000000, 0.000000 ) 0.47410482 WF centre and spread 5 ( 0.000000, 0.000000, 0.000000 ) 0.45975935 WF centre and spread 6 ( -0.889018, 0.889018, 0.889018 ) 1.83568265 WF centre and spread 7 ( 0.889018, -0.889018, -0.889018 ) 1.83568265 Sum of centres and spreads ( 0.000000, 0.000000, 0.000000 ) 5.99885597 Spreads (Ang^2) Omega I = 5.398459543 ================ Omega D = 0.006910496 Omega OD = 0.593485936 Final Spread (Ang^2) Omega Total = 5.998855975 ------------------------------------------------------------------------------ Omega Invariant: 1-s^2 = 5.398459543 (Ang^2) -2log s = 5.917906434 (Ang^2) acos^2 = 5.729169696 (Ang^2) Wannier Function Num: 1 Maximum Im/Re Ratio = 0.075234 Wannier Function Num: 2 Maximum Im/Re Ratio = 0.632363 Wannier Function Num: 3 Maximum Im/Re Ratio = 0.718934 Wannier Function Num: 4 Maximum Im/Re Ratio = 0.071312 Wannier Function Num: 5 Maximum Im/Re Ratio = 1.014505 Wannier Function Num: 6 Maximum Im/Re Ratio = 2.203505 Wannier Function Num: 7 Maximum Im/Re Ratio = 3.094914 ***.win file: begin projections Cu:d f=0.25,0.25,0.25:s f=-0.25,-0.25,-0.25:s end projections num_wann 7 iprint 5 dis_win_min 0.000 dis_win_max 40.000 dis_froz_min 0.000 dis_froz_max 20.000 num_iter 3000 search_shells 20 Begin Kpoint_Path G 0.00 0.00 0.00 X 0.50 0.50 0.00 X 0.50 0.50 0.00 W 0.75 0.50 0.25 W 0.75 0.50 0.25 L 0.50 0.50 0.50 L 0.50 0.50 0.50 G 0.00 0.00 0.00 G 0.00 0.00 0.00 K 0.75 0.3750 0.3750 End Kpoint_Path bands_plot = .true. wannier_plot = true num_bands = 15 dis_num_iter=9000 dis_mix_ratio=0.2 guiding_centres = T ***pwscf.in: &control calculation='scf', prefix='Cu', pseudo_dir = '../../pp/', outdir='./', / &system ibrav = 2 , celldm(1) = 6.72 , nat= 1 , ntyp = 1 , ecutwfc = 80.0 occupations = 'smearing', smearing = 'marzari-vanderbilt' nbnd = 15 degauss = 0.001 nosym=.true. / &electrons mixing_beta = 0.1 conv_thr = 1.0d-8 / ATOMIC_SPECIES Cu 63.55 Cu.pw-mt_fhi.UPF ATOMIC_POSITIONS crystal Cu 0.000000000 0.000000000 0.000000000 K_POINTS AUTOMATIC 16 16 16 0 0 0 Thank you!! Jennifer Jennifer L. Wohlwend Universal Technology Corporation -------------- next part -------------- An HTML attachment was scrubbed... URL: From jonathan.yates at materials.ox.ac.uk Mon Aug 5 21:01:57 2013 From: jonathan.yates at materials.ox.ac.uk (Jonathan Yates) Date: Mon, 5 Aug 2013 19:01:57 +0000 Subject: [Wannier] large Im/Re In-Reply-To: References: Message-ID: <78877D222077A642A4CFAB09BD0077E001066ECD@MBX10.ad.oak.ox.ac.uk> Jennifer, Your WF are 'nearly' real. I think the problem might be due to the positioning of the windows. You see from the band-structure of copper that if your frozen window is a little too high you force your WF to capture the character of some different bands. So in this case the inner window can only be a few eV above the Fermi level (if you wanted to capture higher bands, you might try 9 MWLF). It is helpful to compare the bands from PWSCF to those computed by W90 - that will guide you to a good choice for the windows. Copper is a well studied example - it was in the original disentanglement paper of Souza, Marzari and Vanderbilt. You will find input files for copper as example06 of the Wannier90 distribution. This will converge to give real MLWF in small number of steps. Yours Jonathan On 5 Aug 2013, at 19:31, Jennifer Wohlwend wrote: > Dear all, > I'm using WANNIER90 (Release: 1.1.1) as a library with pwscf and epw.x for Copper. Although I'm using the same starting projections as the example (I've also tried starting with 'random') with 15 bands (7 WFs) and an 8x8x8 k-point mesh the Im/Re ratio is still quite high especially for the interstitial WF (6 and 7). The spread is also somewhat larger than the example found here:http://www.tcm.phy.cam.ac.uk/~jry20/wannier/copper.html. > The band structure reproduces well and the visualization of the (1-5) WF look like 3dx2-y2 , 3dz2 , 3dxy, 3dxz, and 3dyz orbitals whereas the 6 & 7 WF look like distorted s orbitals. I've included guiding_centres = T as well but I'm still getting imaginary WF. I have included the center/spread data, Im/Re ratio data, the .win file created by epw.x as well as the pwscf.in file for my system. Thank you in advance for any suggestions on how to remedy this situation. > -- Department of Materials, University of Oxford, Parks Road, Oxford, OX1 3PH, UK tel: +44 (0)1865 612797 http://users.ox.ac.uk/~oums0549/ From zikuiliu at gmail.com Sun Aug 11 03:09:51 2013 From: zikuiliu at gmail.com (Zikui Liu) Date: Sat, 10 Aug 2013 21:09:51 -0400 Subject: [Wannier] How to set num_wann? Message-ID: Dear all, I am a new user of wannier90. I have a quick question to ask you for help, i.e. How to set num_wann in a ".win" file? Does it equal to the number of valence bands? Thank you in advance. Zikui -------------- next part -------------- An HTML attachment was scrubbed... URL: From nicola.marzari at epfl.ch Sun Aug 11 12:37:39 2013 From: nicola.marzari at epfl.ch (Nicola Marzari) Date: Sun, 11 Aug 2013 12:37:39 +0200 Subject: [Wannier] How to set num_wann? In-Reply-To: References: Message-ID: <52076973.7030309@epfl.ch> On 11/08/2013 03:09, Zikui Liu wrote: > Dear all, > > I am a new user of wannier90. I have a quick question to ask you for > help, i.e. > > How to set num_wann in a ".win" file? > > Does it equal to the number of valence bands? > > Thank you in advance. > > Zikui > Dear Zikui, it is the number of Wannier functions you want. It would be say 4 for an insulator (e.g. GaAs) where you want to transform the entire valence manifold. But, in the same system, it could be 1 (e.g. to transform the lower valence band)), 3 (for the upper 3 valence bands), 8 (to transform both occupied and empty manifold - with the need also of disentanglement...). nicola ---------------------------------------------------------------------- Prof Nicola Marzari, Chair of Theory and Simulation of Materials, EPFL From gfiori at mercurio.iet.unipi.it Fri Aug 30 10:25:27 2013 From: gfiori at mercurio.iet.unipi.it (Gianluca Fiori) Date: Fri, 30 Aug 2013 10:25:27 +0200 Subject: [Wannier] New Release of the open-source NanoTCAD ViDES code Message-ID: We are pleased to announce that a new version of the open-source NanoTCAD ViDES code has been released and available for download at http://vides.nanotcad.com The code is now able to interface with Wannier90 in order to perform multi-scale simulations of nanoscale devices. Look at the tutorial on multi-scale simulations of functionalized graphene nanoribbon Field Effect Transistors for an understanding of its capabilities ( http://vides.nanotcad.com/vides/documentation/tutorials/tutorial-14-multi-scale-gnr-fet-simulation ). The code efficiently computes transport in generic structures defined at run time by the user and it is particularly geared towards the performance assessment of carbon/graphene based devices through the self-consistent solution of Poisson and transport equations. Enjoy! -------------- next part -------------- An HTML attachment was scrubbed... URL: