[Wannier] Question about final spreads
lan haiping
lanhaiping at gmail.com
Tue Dec 19 03:54:14 CET 2006
Dear Nicola,
Thank you.
I do want to repeat Prof Postermak's works on tio2.
Last night, i also tried to change projection functions for rutile tio2.
Indeed, i also found there
are 2 more minimum spreads founded with different stating projection
functions.
For rutile case, when i started with s/px/py/pz on O sites, i obtained total
spreads of 14.919. while changing projection functions to sp2/pz on O
sites, i obtained total spreads of 14.4672. But wannier function centers
can both be classified into 4 groups.
Regards,
Hai-Ping
On 12/18/06, Nicola Marzari <marzari at mit.edu> wrote:
>
>
>
> Dear Hai-Ping,
>
>
> I believe Michel Posternak has published a paper on Ti02 Wannier
> functions. It would be interesting to compare your results to his.
>
> Our consensus was that the localization functional can display
> minima that are not meaningful - usually marked by the fact that the
> MLWFs do not look localized, or symmetric, and especially that they are
> not real-valued, but are complex-valued. These incorrect minima are
> somewhat connected to the fact that there are few points in the BZ where
> a smooth continuous choice of phase factors was not achieved.
>
> There are cases when more than one good minimum can exist - the first
> one that comes to my mind is benzene, where you can have two equivalent
> choices for the location of the three double bonds on the aromatic ring.
>
> It could be that yours is another case - there is more that one
> meanigful minimum - and, the notion of "meaningful minimum" is rather
> heuristic.
>
> Let us know what you find,
>
> nicola
>
>
>
>
> lan haiping wrote:
> > Dear All,
> >
> > I came to confusion about final results of wannierise procedure.
> > I am trying to analyse anatase tio2 wannier function and born charge
> > with wannier90.x.
> > I performed 2 calculations with 2 different projection functions sets,
> > other settings are same. Both reached convergenc (error deltas for total
> > Omega are about 1E-10). But the total spreads and wannier centers are
> > quite different.
> > For my first calculation, i just start with sp2 and pz functions at O
> > sites, the total spreads finally obtained is 14.397.
> > While for the second calculation, the projetion functions are s/px/py/pz
> > functions at O sites, the total spreads finally obtained is then
> > 15.2170.
> >
> > The wannier functions of second calculation could be classed into 4
> > groups by spreads , while the conclusion is not hold for the fist
> > calculation ( the wannier functions are then classed into 8 groups ).
> >
> > According to MV paper, the MLWFs reflect structures' symmetry by
> > spreads. So, Both 2 calculations are not correct.
> >
> > Would you please give me some comments ?
> > And input files are below :
> >
> > *num_wann = 16
> > num_iter = 2000
> > guiding_centres = T
> > exclude_bands = 1 2 3 4 5 6 7 8 25 26 27 28 29 30
> > begin projections
> > O : sp2
> > O : pz
> > end projections
> > begin atoms_cart
> > Ti 0.000000000 -0.000000000 0.000000000
> > Ti 0.000000000 1.892500000 2.378500000
> > O 0.000000000 0.000000000 1.979863400
> > O 0.000000000 -0.000000000 7.534136600
> > O 0.000000000 1.892500000 4.358363400
> > O 0.000000000 1.892500000 0.398636600
> > end atoms_cart*
> >
> > *begin unit_cell_cart
> > Ang
> > 1.8925 -1.8925 4.757
> > 1.8925 1.8925 4.757
> > -1.8925 -1.8925 4.757
> > end unit_cell_cart
> > mp_grid : 6 6 6
> > begin kpoints
> > ......
> > end kpoints*
> >
> > two final spreads and wannier centers are attached.
> >
> > *Regards*
> >
> > Hai-Ping
> >
> >
> >
> > --
> > Hai-Ping Lan
> > Department of Electronics ,
> > Peking University , Bejing, 100871
> >
> >
> > ------------------------------------------------------------------------
>
> >
> > Final State
> > WF centre and spread 1 ( -0.057359, 0.368438, 2.144012 )
> 0.81913203
> > WF centre and spread 2 ( -0.057359, -0.368438, 2.144012 )
> 0.81913201
> > WF centre and spread 3 ( 0.207447, 0.000000, 1.889906 )
> 1.06292459
> > WF centre and spread 4 ( -0.197679, 0.225730, 7.480939 )
> 0.95045581
> > WF centre and spread 5 ( -0.197683, -0.225729, 7.480937 )
> 0.95045348
> > WF centre and spread 6 ( 0.383935, 0.000000, 7.384053 )
> 0.82485652
> > WF centre and spread 7 ( -0.197693, 2.118226, 4.411569 )
> 0.95044526
> > WF centre and spread 8 ( -0.197669 , 1.666767, 4.411555 )
> 0.95046140
> > WF centre and spread 9 ( 0.383935, 1.892503, 4.508447 )
> 0.82485530
> > WF centre and spread 10 ( -0.057359, 2.260938, 0.234488 )
> 0.81913205
> > WF centre and spread 11 ( - 0.057359, 1.524062, 0.234488 )
> 0.81913192
> > WF centre and spread 12 ( 0.207447, 1.892500, 0.488594 )
> 1.06292460
> > WF centre and spread 13 ( -0.090800, 0.000000, 1.575406 )
> 0.88848488
> > WF centre and spread 14 ( 0.012349, 0.000000, 7.957177 )
> 0.88317336
> > WF centre and spread 15 ( 0.012349, 1.892503, 3.935322 )
> 0.88317159
> > WF centre and spread 16 ( -0.090800 , 1.892500, 0.803094 )
> 0.88848495
> > Sum of centres and spreads ( 0.005703, 15.139999, 57.083998 )
> 14.39721976
> >
> >
> > ------------------------------------------------------------------------
>
> >
> > Final State
> > WF centre and spread 1 ( 0.000000, 0.000000, 1.913455 )
> 1.16247952
> > WF centre and spread 2 ( 0.000000, 0.000000, 7.509543 )
> 1.20049037
> > WF centre and spread 3 ( 0.000000, 1.892500, 4.382956 )
> 1.20048903
> > WF centre and spread 4 ( 0.000000, 1.892500, 0.465045 )
> 1.16247952
> > WF centre and spread 5 ( 0.000000, 0.000000, 2.004457 )
> 1.20048828
> > WF centre and spread 6 ( 0.000000, 0.000000, 7.600545 )
> 1.16248168
> > WF centre and spread 7 ( 0.000000, 1.892500, 4.291955 )
> 1.16248025
> > WF centre and spread 8 ( 0.000000 , 1.892497, 0.374043 )
> 1.20048827
> > WF centre and spread 9 ( 0.000000, 0.000000, 1.522196 )
> 0.75151445
> > WF centre and spread 10 ( 0.000000, 0.000000, 7.991803 )
> 0.75151691
> > WF centre and spread 11 ( 0.000000, 1.892500, 3.900696 )
> 0.75151511
> > WF centre and spread 12 ( 0.000000, 1.892501, 0.856304 )
> 0.75151453
> > WF centre and spread 13 ( 0.000000, 0.000000, 2.312422 )
> 0.68819033
> > WF centre and spread 14 ( 0.000000, 0.000000, 7.201578 )
> 0.68819219
> > WF centre and spread 15 ( 0.000000, 1.892500, 4.690922 )
> 0.68819114
> > WF centre and spread 16 ( 0.000000 , 1.892502, 0.066078 )
> 0.68819026
> > Sum of centres and spreads ( 0.000000, 15.139999, 57.083998 )
> 15.21070184
>
>
> --
> ---------------------------------------------------------------------
> 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
> _______________________________________________
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>
--
Hai-Ping Lan
Department of Electronics ,
Peking University , Bejing, 100871
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