Uniform sampling = no

Deals with issues related to electron-phonon coupling calculations

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Sam-2025
Posts: 34
Joined: Mon Jan 06, 2025 1:23 pm

Uniform sampling = no

Post by Sam-2025 » Tue Jun 10, 2025 6:26 am

Dear all,


I would like to recheck the band gap vs Temperature for cubic BTO, using the following tutorial :https://wiki.yambo-code.eu/wiki/index.p ... n_Coupling
I ran scf and nscf using kpoint 6 6 6 and as mentioned in the tutorial I got the following "Q-points (IBZ) PW-formatted" = #20, then I ran phonon and DVSCF calculation(attached the input files), but after running ypp_ph, I got "Uniform sampling :no", , is it should be yes ? I mean when it is "no", how it can affect the result? Could you please let me know, what shall I do to reach a Uniform sampling?
Then
I tried to continue the tutorial and ran for different temperature, but my gap vs T, does not look correct! Also, could you please guide me , how should I choose the "QPkrange " variable in this section. BTO has indirect band gap from R to Gamma point and VBM = 20. Your guidance would be very useful for me. Thank you so much in advance.

<---> Q-points (IBZ) PW-formatted
0.000000000 0.000000000 0.000000000 1
0.000000000 0.000000000 0.166666642 1
0.000000000 0.000000000 0.333333284 1
0.000000000 0.000000000 -0.500000000 1
0.000000000 0.166666642 0.166666642 1
0.000000000 0.166666642 0.333333284 1
0.000000000 0.166666642 -0.500000000 1
0.000000000 0.333333284 0.333333284 1
0.000000000 0.333333284 -0.500000000 1
0.000000000 -0.500000000 -0.500000000 1
0.166666642 0.166666642 0.166666642 1
0.166666642 0.166666642 0.333333284 1
0.166666642 0.166666642 -0.500000000 1
0.166666642 0.333333284 0.333333284 1
0.166666642 0.333333284 -0.500000000 1
0.166666642 -0.500000000 -0.500000000 1
0.333333284 0.333333284 0.333333284 1
0.333333284 0.333333284 -0.500000000 1
0.333333284 -0.500000000 -0.500000000 1
-0.500000000 -0.500000000 -0.500000000 1
<---> [08] Timing Overview
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Samira Ghanbarzadeh (she/her)
PhD Student
Mechanical Engineering Department / UVM

Sam-2025
Posts: 34
Joined: Mon Jan 06, 2025 1:23 pm

Re: Uniform sampling = no

Post by Sam-2025 » Tue Jun 10, 2025 6:27 am

scf, nscf files also attached for your consideration.
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Samira Ghanbarzadeh (she/her)
PhD Student
Mechanical Engineering Department / UVM

Sam-2025
Posts: 34
Joined: Mon Jan 06, 2025 1:23 pm

Re: Uniform sampling = no

Post by Sam-2025 » Sun Jun 15, 2025 3:41 pm

Dear all,

no one had this issue before? any guidance would be very useful. Thank you so much in advance.
Samira Ghanbarzadeh (she/her)
PhD Student
Mechanical Engineering Department / UVM

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