Gap energy abruptly goes negative at high temperatures

[hpaudya1]

Hi Makhail,

Ans. 1. No, unfortunately.
Ans. 2. Yes, you can tune fine k/q grids. I do not think the denser grids decrease the necessary wscut value.

One thing I noticed is "Cutoff frequency wscut = 4.7690 and 3.9027". This looks very high to me now. Because of this, your calculation is taking a long time. I already said, try wscut 10 times the maximum phonon frequency at the lowest temp and fix the nsiw same for the larger temps.

Best,
Hari

[CHILLL]

Hello Hari,

Yes, those values are very high indeed, but I am forced to increase wscut otherwise I get negative gap values again.
Is there maybe something else I can try?

Best,
Mikhail

[mxh]

Dear Mikhail,
I have encountered the same problem as you. The negative gap energy exits in higher temperatures. Wannier functions are good. Is it feasible to increase the value of "wscut"? Can you tell me how to solve this problem?

Thank you!
Best,
mxh