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Dear Zeina,
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<div>There is no "exact" value for these flags. dist_cutoff sets to zero the hoppings for WF farther than this distance. You can do a bulk calculation, see when the hoppings are sufficiently small, and use that distance as a rough estimate of dist_cutoff. To
know if the choice was a good one, try to calculate e.g. the band structure with that dist_cutoff and see if it changes significantly (if it does, the cutoff was too small). As any convergence parameter, it is always a compromise between accuracy and computational
cost of the calculation, the larger the better, but also if you do a LCR calculation you will need to take into account larger principal layers and thus you will need to make a more expensive calculation. </div>
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<div>For tran_win_min and tran_win_max, these simply identify the energy window range in which you want to calculate the transport. Do a band structure to identify the relevant bands and their energy window, and use that range as a transport energy window.
Note that you can always rerun the calculation later with a different window, in case of doubt. The computational cost is in good approximation a constant times the # of energy points you use, so the larger the window, the more points you calculate. In case
of doubt, you can take a larger window with a coarser energy grid in a first step (parameter tran_energy_step) and then do a calculation on a finer grid in the energy window of interest.</div>
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<div>Looking into examples/tutorials may be of help, see for instance the Santa Barbara school (and the other tutorials, too) here: <a href="http://wannier.org/user_guide.html">http://wannier.org/user_guide.html</a></div>
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<div>Best,</div>
<div>Giovanni</div>
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<div>-- </div>
<div>Giovanni Pizzi<br>
Post-doctoral Research Scientist<br>
EPFL STI IMX THEOS<br>
MXC 340 (Bātiment MXC)<br>
Station 12<br>
CH-1015 Lausanne (Switzerland)<br>
Phone: +41 21 69 31124<br>
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<div>On 18 Nov 2014, at 23:54, Zeina Al-Dolami wrote:</div>
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<div dir="ltr">Thanks Dr. Giovanni for your detailed answer. I have another question about dist_cutoff, tran_win_min, and tran_win_max. I know what they represent as they are clarified in the user manual. However, I am confused about their values. My question
is are they chosen approximately? or there is a specific way to find their exact values? I have been looking into many references, but none of them is given the answer that I am looking for. It might be explained elsewhere that I am not aware of. Any answer
is appreciated as I am still learning how to use wannier90. Looking forward to hearing from you and many thanks in advance
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<div>Zeina </div>
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