Dear EPW users
The energy range of EPW band structure and QE is not the same as shown in the attached Figure.
One can see from the Figure that the xaxis for QE bands is from 0 to 1.56 eV, while for EPW bands, it is 0 to 1.8 eV.
Due to this, the EPW bands are not overlapping with the QE band structure.
This type of problem does not occur with phonon band structure which looks fine.
I did many calculations by changing the frozen energy window and which wannier bands to plot, etc., but I am getting similar results every time.
Could anybody help me how to get EPW bands similar to QE?
Best Regards
Showkat
HRI, Allahabad, India.
Different energy range of band structure in EPW and Quantum espresso
Moderator: hlee

 Posts: 23
 Joined: Tue Aug 21, 2018 11:24 am
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Different energy range of band structure in EPW and Quantum espresso
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Re: Different energy range of band structure in EPW and Quantum espresso
Hi Showkat,
The xaxis is not the energy axis, it is the wavevector (high symmetry direction).
Could you doublecheck the coordinate of your highsymmetry points in QE band calculation and EPW? It would be to help you if you could provide your input files.
Best,
Hari Paudyal
The xaxis is not the energy axis, it is the wavevector (high symmetry direction).
Could you doublecheck the coordinate of your highsymmetry points in QE band calculation and EPW? It would be to help you if you could provide your input files.
Best,
Hari Paudyal

 Posts: 23
 Joined: Tue Aug 21, 2018 11:24 am
 Affiliation:
Re: Different energy range of band structure in EPW and Quantum espresso
Dear Hari Paudyal
Thank you for correcting me; the xaxis is the wavevector, true.
The number of highsymmetry kpoints used in EPW calculations is taken from QE bands.out file.
The total number of Kpoints was the same in both the calculations.
The files are attached herewith.
Thank you for your mail
best regards
SHowkat
Thank you for correcting me; the xaxis is the wavevector, true.
The number of highsymmetry kpoints used in EPW calculations is taken from QE bands.out file.
The total number of Kpoints was the same in both the calculations.
The files are attached herewith.
Thank you for your mail
best regards
SHowkat
 Attachments

 PtS2.zip
 (26.27 KiB) Downloaded 34 times
Re: Different energy range of band structure in EPW and Quantum espresso
Hi SHowkat,
Could you please use crystal coordinates instead 2pi/alat in the EPW calculation?
Best,
Hari
Could you please use crystal coordinates instead 2pi/alat in the EPW calculation?
Best,
Hari

 Posts: 23
 Joined: Tue Aug 21, 2018 11:24 am
 Affiliation:
Re: Different energy range of band structure in EPW and Quantum espresso
Dear Hari Paudyal
So nice of you to help me to solve my problem.
The bands are now precisely overlapping by using the crystal coordinates.
Thanks a ton.
best regards
Showkat
So nice of you to help me to solve my problem.
The bands are now precisely overlapping by using the crystal coordinates.
Thanks a ton.
best regards
Showkat
Re: Different energy range of band structure in EPW and Quantum espresso
Hi Showkat,
Great to know that your problem is solved. There might be some issue with the 2pi/alat coordinate in the implementation, I will have a look at it and update if required.
Happy EPWing,
Hari
Great to know that your problem is solved. There might be some issue with the 2pi/alat coordinate in the implementation, I will have a look at it and update if required.
Happy EPWing,
Hari