[Wannier] band structure interpolation ends up with wiggly bands

[Nicola Marzari]

Mostly welcome! I hadn't realized your first run was done without 
disentanglement -
something that should always be done when bands are, well, entangled.

				nicola



On 12/02/2015 06:44, Yu Zhang wrote:
> Dear Nicola,
>
> Thank you for your reply, I have tried before to project the wannier
> function without spin-orbit, I can get smooth bands. But in that case, I
> used disentanglement method instead of excluding bands. Simply excluding
> the bands may cause the problem. Aron also suggests me to use
> disentanglement method and set sp3 hybrid as initial projection.
>
> Thank you for your suggestions.
>
> Best regards,
>
> Yu
>
> On Wed, Feb 11, 2015 at 10:29 PM, Nicola Marzari <nicola.marzari at epfl.ch
> <mailto:nicola.marzari at epfl.ch>> wrote:
>
>
>     Dear Yu,
>
>
>     my first guess is that if you want to disentangle the 5d bands,
>     and use 12 wannier functions, you need to include the
>     bottom of the parabolic "s" band - i.e. bands 1-2,
>     as in Fig. 4a of the Souza et al 2002 PRB.
>
>     Why don't you try this first in gold without spin-orbit, and see
>     if you can reproduce the results above (those where for copper,
>     but the same considerations apply).
>
>                              nicola
>
>
>
>     On 11/02/2015 20:16, Yu Zhang wrote:
>
>         Dear wannier90 users and developers,
>
>         I am using wannier90-1.2 and vasp5.3 to obtain the wannier wave
>         function
>         of gold with spin-orbital coupling. I used d5s orbital as target.
>         However, it ends up with some wiggly bands as shown by the attached
>         figure. I have tried different projection (d5), and k-mesh, but
>         I still
>         failed to get the smooth bands. Does anyone know what causes the
>         wiggly
>         bands and how to get rid of them?
>
>
>         My wannier90 input file is:
>         ==============================__=============
>         num_wann  = 12  ! set to NBANDS by VASP
>         num_bands = 12
>
>         exclude_bands : 1-2, 15-16
>
>         spinors = .true.
>         Begin Projections
>         Au: l=0;l=2
>         End Projections
>
>         begin unit_cell_cart
>                0.0000000     2.0340000     2.0340000
>                2.0340000     0.0000000     2.0340000
>                2.0340000     2.0340000     0.0000000
>         end unit_cell_cart
>
>         begin atoms_cart
>         Au       0.0000000     0.0000000     0.0000000
>         end atoms_cart
>
>         mp_grid =    21    21    21
>
>         begin kpoints
>                 0.000000000000      0.000000000000      0.000000000000
>                 0.047619047619      0.000000000000      0.000000000000
>                 0.095238095238      0.000000000000      0.000000000000
>                 0.142857142857      0.000000000000      0.000000000000
>                 0.190476190476      0.000000000000      0.000000000000
>         .......
>         ==============================__====================
>
>         Thank you very much in advance!
>
>         Best regards,
>
>         Yu Zhang
>
>
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>
>
>     --
>
>     ------------------------------__------------------------------__----------
>     Prof Nicola Marzari, Chair of Theory and Simulation of Materials, EPFL
>
>

-- 

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Prof Nicola Marzari, Chair of Theory and Simulation of Materials, EPFL