[Wannier] Wannier functions for phosphorene

[Vahid Askarpour]

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