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

[Carmine Autieri]

Great, thank you very much.

Carmine Autieri

----- Messaggio originale -----
Da: "Nicolas Lorente" <nicolas.lorente at cin2.es>
A: wannier at quantum-espresso.org
Inviato: Mercoledì, 2 maggio 2012 16:15:35
Oggetto: Re: [Wannier] hopping in supercell, wich k-points grid?


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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