[Wannier] Wannier functions for phosphorene
Vahid Askarpour
vh261281 at dal.ca
Wed May 4 14:40:34 CEST 2016
Dear Wannier Users,
Further to my query concerning the large spread in the Wannier functions of Phosphorene, I have found that for this structure, even the spread of the 10 Wannier functions of the valence band are dependent upon the number of bands in the DFT calculation. I first used 16 bands in DFT, but for Wannier analysis, I excluded bands 11-16. I get the following spreads:
Final State
WF centre and spread 1 ( 0.032619, -0.001266, 1.071738 ) 1.64069781
WF centre and spread 2 ( 1.664124, 2.180066, 1.073067 ) 1.64160850
WF centre and spread 3 ( 0.849094, 1.087359, 2.031593 ) 1.63889583
WF centre and spread 4 ( 0.853572, 3.270004, 0.113789 ) 1.64289554
WF centre and spread 5 ( 1.659337, 2.256282, -0.306527 ) 2.04709099
WF centre and spread 6 ( 2.480884, 3.258792, 0.108274 ) 1.64433084
WF centre and spread 7 ( 1.664159, 2.091514, 2.448504 ) 2.06656396
WF centre and spread 8 ( 0.031649, 0.083655, 2.447674 ) 2.06578072
WF centre and spread 9 ( 2.480164, 1.088250, 2.030320 ) 1.64259413
WF centre and spread 10 ( 3.294805, -0.083020, -0.303269 ) 2.06940059
Sum of centres and spreads ( 15.010408, 15.231636, 10.715164 ) 18.09985893
Then I included 24 bands in DFT, excluded 11-24 and got the following:
Final State
WF centre and spread 1 ( 3.232235, 4.221211, 1.464594 ) 1.53600401
WF centre and spread 2 ( 2.225527, 3.097919, 0.164328 ) 2.52306202
WF centre and spread 3 ( 3.257786, -0.033530, -0.233035 ) 1.95662307
WF centre and spread 4 ( 1.531352, 2.622350, -0.045056 ) 3.12446143
WF centre and spread 5 ( -2.120340, 0.967092, 1.968996 ) 2.09950243
WF centre and spread 6 ( 1.084863, 2.870595, -0.113348 ) 1.91457968
WF centre and spread 7 ( 1.879941, 2.425977, 0.961497 ) 1.48248823
WF centre and spread 8 ( 2.304219, 1.536780, 2.222690 ) 3.81535194
WF centre and spread 9 ( 3.225247, 0.150051, 2.122159 ) 2.92019866
WF centre and spread 10 ( 1.636450, 1.739929, 2.256592 ) 4.30047110
Sum of centres and spreads ( 18.257280, 19.598375, 10.769417 ) 25.67274257
Since I am not including conduction bands in the analysis (no disentanglement), I expect to get almost the same outcome. Or should I?
I would appreciate any hint as to what I am missing here.
Thank you,
Vahid
> On May 1, 2016, at 9:07 AM, Vahid Askarpour <vh261281 at dal.ca> wrote:
>
> Dear Wannier Users,
>
> In the Wannier forum (http://mailman.qe-forge.org/pipermail/wannier/2015-June/001041.html),
> it is suggested that Wannier functions can be generated for phosphorene (10 valence+6 conduction) using sp3 projection but I noticed that the spreads are large. I have included the .win file at the end. The windows are consistent with the energy values in the .eig file.
>
> Final State
> WF centre and spread 1 ( 0.058106, 0.364134, 2.203320 ) 6.42369489
> WF centre and spread 2 ( 0.363382, 0.029268, 1.768449 ) 5.62174328
> WF centre and spread 3 ( -0.172524, 0.579602, 1.691755 ) 4.81604151
> WF centre and spread 4 ( -0.341139, 0.008715, 2.377388 ) 2.87367367
> WF centre and spread 5 ( 0.360205, 4.104384, 0.301798 ) 6.77275356
> WF centre and spread 6 ( 0.278114, 3.655974, -0.149721 ) 9.99901839
> WF centre and spread 7 ( -0.333338, 4.269468, -0.284828 ) 2.58433508
> WF centre and spread 8 ( -0.275708, 3.519428, 0.280193 ) 5.61317656
> WF centre and spread 9 ( 1.991154, 2.086262, 2.485397 ) 3.43708409
> WF centre and spread 10 ( 1.873663, 1.416381, 1.724219 ) 4.87405020
> WF centre and spread 11 ( 1.241545, 1.999978, 1.887498 ) 8.12099445
> WF centre and spread 12 ( 1.156877, 1.269852, 2.309786 ) 6.38132297
> WF centre and spread 13 ( 1.763745, 2.722892, 0.508121 ) 5.00442371
> WF centre and spread 14 ( 2.010286, 2.198255, -0.297114 ) 2.96185255
> WF centre and spread 15 ( 1.402020, 2.786170, -0.099259 ) 9.53353884
> WF centre and spread 16 ( 1.312590, 2.118950, 0.458781 ) 5.36088784
> Sum of centres and spreads ( 12.688979, 33.129715, 17.165781 ) 90.37859158
>
> Spreads (Ang^2) Omega I = 50.276462026
> ================ Omega D = 0.742952236
> Omega OD = 39.359177316
> Final Spread (Ang^2) Omega Total = 90.378591577
>
>
> I do get very small spreads when I consider only the valence bands though. I would appreciate any suggestions as to how the spreads can be minimized.
>
> Thank you,
>
> Vahid
>
> Vahid Askarpour
> Department of Physics and Atmospheric Science
> Dalhousie University
> Halifax, NS Canada
>
>
> num_wann = 16
> num_iter = 100
> dis_win_max=6
> dis_froz_max= -0.1
>
> begin atoms_frac
> P 0.010000000 0.081190508 0.152288548
> P 0.010000000 0.918809429 0.001303918
> P 0.510000000 0.418809492 0.152288548
> P 0.510000000 0.581190571 0.001303918
> end atoms_frac
>
> begin projections
> P:sp3
> end projections
>
> begin unit_cell_cart
> bohr
> 6.166298 0 0
> 0 8.2238498 0
> 0 0 26.362484
> end_unit_cell_cart
>
> mp_grid : 10 10 1
>
> begin kpoints
> 0.0000000000000 0.0000000000000 0.0000000000000 0.0100000000000
> 0.0000000000000 0.1000000000000 0.0000000000000 0.0100000000000
> 0.0000000000000 0.2000000000000 0.0000000000000 0.0100000000000
> 0.0000000000000 0.3000000000000 0.0000000000000 0.0100000000000
> 0.0000000000000 0.4000000000000 0.0000000000000 0.0100000000000
> 0.0000000000000 0.5000000000000 0.0000000000000 0.0100000000000
> …..
> …..
> end kpoints
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