[Wannier] hopping in supercell, wich k-points grid?

[Nicolas Lorente]

On 02/05/12 15:46, Carmine Autieri wrote:
> Dear Wannier90 users, I kindly ask a simple suggestion.
>
> I am trying to calculate the hopping parameters in a supercell with a large z-axis using wannier90.
>
> The z-axis is 10 times longer than the other axes. Morover, the system is quasi two-dimensional.
> I used 10 X 10 X 1 k-points grid. Is it enough for a good estimation of hopping parameters?
> The calculation is very expensive for my machine. Do you think that a 8 X 8 X 2 grid should be really better?
>
> thanks
> Carmine Autieri
> Universita' di Salerno (Italy)
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I'd use the same k-point sampling as for the DFT calculation to start 
with. Plot the bands and check if the wannier bands are in good agreement.

I would not use 8x8x2, but 8x8x1 eventually.

Start with the smallest k-point sampling, check the bands and increase 
if the agreement should be better. It will depend on what you want to 
do, etc ... of course, you should also pay attention to the energy 
windows, disentanglement, spread, etc that are probably more important 
than the k-point sampling to get good bands. Try a smaller system first.


Hope this helps,

Nicolás

-- 
Nicolás Lorente
Centro de Investigación en Nanociencia y Nanotecnología
Campus de la UAB
E-08193 Bellaterra
Tel. (+34) 935868410

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