[Wien] how to increase precision of calculations?

[tran at theochem.tuwien.ac.at]

Hi,
For the convergence, I suggest to increase RKmax further. RKmax=8 is
(very) good, but also not fully converged usually. Going up to
RKmax=10 makes sense.

It's difficult to say for the step at 0.003. Maybe the k-mesh is still
not dense enough. An increase of GMAX (12 -> 18) in case.in2 is worth to
try.

F. Tran

On Sat, 29 Nov 2014, Martin Gmitra wrote:

> Dear Wien2k users,
>
> We are calculating spin-orbit coupling splitting of valence band in
> wurtzite GaAs using mBJ. Since we are interested in a fine structure
> close to Gamma point, we need to achieve sufficient accuracy. I am
> attaching a plot of the valence band spin-orbit coupling splitting
> (divided by the amplitude of k) as a function of k from the Gamma
> point (k=0). As you can see, the splitting is sensitive to RKmax and
> it does not look like it is going to "converge". What bothers me in
> addition, is the step in the curves around 0.003 which can not be
> healed by increasing RKmax (a smooth behavior as close as possible to
> the Gamma point is desired result). I would like to add that
> increasing k-mesh density does not affect the results as well as
> increasing IFFT factor or reducing RMTs.
>
> Do you have any suggestions?
> Best regards,
> Martin Gmitra
> Uni Regensburg
>