[Wannier] Convergence problem of wannierisation

[Arash Mostofi]

Dear Hongbin,

Others who have studied this particular system may be able to give more
specific advice.

The first things I would check are that you are including a sufficient
number of conduction bands for the disentanglement, using an appropriate
inner (or "frozen") wiindow and appropriate initial guesses
("projections") for your Wannier functions.

Best wishes,

Arash

:------------------------------------------------------------:
: Dr. Arash A. Mostofi           :: a.mostofi at imperial.ac.uk :
: Lecturer and RCUK Fellow       ::                          :
: Depts. of Materials & Physics  ::                          :
: Imperial College London        :: T  +44 (0)207 594 8154   :
: London SW7 2AZ, United Kingdom :: F  +44 (0)207 594 6757   :
:------- http://www.cmth.ph.ic.ac.uk/people/a.mostofi -------:

Zhang, Hongbin wrote:
> Dear all,
> 
> At present I am trying to play with Wannier 90 to calculate some properties like anomalous Hall effect. However, I found that sometimes it is hard to get the convergence of minimazation of both the Omega_I and Omega, that is, disentanglement and wannierization. This is true especially for the latter. I have tried on hcp Co, following the paper by E. Roman (Phys. Rev. Lett. 103, 097203). However, after 5000 iterations, the wannierisation converges to only 1E-7 (enough already? )  like below (Disentanglement has been achieved to 1E-10):
> 
>    4984    -0.148E-06     0.0003041075      106.4767765619   90254.25  <-- CONV
>    4985     0.875E-05     0.0001849761      106.4767853125   90269.00  <-- CONV
>    4986    -0.736E-05     0.0023025636      106.4767779520   90288.01  <-- CONV
>    4987    -0.155E-05     0.0010750558      106.4767764030   90301.06  <-- CONV
>    4988    -0.660E-06     0.0005507459      106.4767757427   90312.06  <-- CONV
>    4989    -0.856E-07     0.0002900457      106.4767756571   90329.45  <-- CONV
>    4990    -0.695E-07     0.0001142533      106.4767755876   90345.29  <-- CONV
>    4991     0.000E+00     0.0001822559      106.4767755865   90350.65  <-- CONV
>    4992    -0.436E-07     0.0001817570      106.4767755429   90369.36  <-- CONV
>    4993    -0.488E-07     0.0001090447      106.4767754941   90383.58  <-- CONV
>    4994     0.000E+00     0.0001206043      106.4767754934   90387.75  <-- CONV
>    4995    -0.697E-07     0.0001203373      106.4767754237   90403.39  <-- CONV
>    4996    -0.312E-06     0.0005823860      106.4767751115   90416.78  <-- CONV
>    4997    -0.471E-07     0.0001267525      106.4767750644   90433.15  <-- CONV
>    4998    -0.410E-07     0.0001274398      106.4767750233   90451.88  <-- CONV
>    4999     0.000E+00     0.0001121615      106.4767750226   90459.01  <-- CONV
>    5000    -0.797E-07     0.0001117099      106.4767749430   90477.35  <-- CONV
> 
> I have tried also different initial projections, but it does not help so much. So could you please tell me how to speed up the convergence process? And how to achieve better convergence?
> 
> I do not see a lot parameters to play with from the input file. Any suggestion is appreciated.
> 
> Best wishes,
> 
> Hongbin Zhang
> 
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