Dear developers,
I met the problem in calculating thermal conductivity using abinit+phono3py. The 3rd interatomic force constants are calculated using finite difference supercell method, in which the force for each displaced supercell is calculated using abinit. However, the thermal conductivity results are not well enough, with a large deviation with experimental results while VASP+phono3py can give a reasonable results. Do you have any idea about accuracy in calculating forces of abinit?
The pseudopotential used in abinit calculations is psp8 form, for Ga and N atoms.
Thanks,
Daosheng
Thermal conductivity calculation using abinit+phono3py
Moderator: amadon
Re: Thermal conductivity calculation using abinit+phono3py
The cutoff energy and the converge criterion used to stop the SCF cycle can affect the quality of the forcesDo you have any idea about accuracy in calculating forces of abinit?
but it's hard to say without looking at your input file.
Re: Thermal conductivity calculation using abinit+phono3py
Can you try to increase the value of boxcutmin from 2 to e.g. 4?
We found some difference when comparing Abinit DFPT phonons with phonopy finite difference method with Abinit forces and we managed to make the phonopy results agree with DFPT by increasing boxcutmin.
BTW: Are you using ADDGRID=True (https://www.vasp.at/wiki/index.php/ADDGRID) in your Vasp calculations?
We found some difference when comparing Abinit DFPT phonons with phonopy finite difference method with Abinit forces and we managed to make the phonopy results agree with DFPT by increasing boxcutmin.
BTW: Are you using ADDGRID=True (https://www.vasp.at/wiki/index.php/ADDGRID) in your Vasp calculations?
Re: Thermal conductivity calculation using abinit+phono3py
Thanks for your reply.
It is weird that abinit+phonopy can produce good phonon dispersion relations compared with vasp+phonopy, where the settings in calculating 2nd IFCs are exactly the same with those in 3rd IFCs calculations.
The input file used for 3rd IFCs calculations is attached which takes 00001 case as an example. For psp8, tests show that a large cutoff energy is needed and 1000 eV is used here. Using supercell size 4*4*3, about 190 W/mK thermal conductivity is obtained with abinit which is much lower than 270 W/mK from VASP.
I will try to increase boxcutmin to find out the difference.
Best,
Daosheng
It is weird that abinit+phonopy can produce good phonon dispersion relations compared with vasp+phonopy, where the settings in calculating 2nd IFCs are exactly the same with those in 3rd IFCs calculations.
The input file used for 3rd IFCs calculations is attached which takes 00001 case as an example. For psp8, tests show that a large cutoff energy is needed and 1000 eV is used here. Using supercell size 4*4*3, about 190 W/mK thermal conductivity is obtained with abinit which is much lower than 270 W/mK from VASP.
I will try to increase boxcutmin to find out the difference.
Best,
Daosheng
 Attachments

 supercell00001.in
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Re: Thermal conductivity calculation using abinit+phono3py
gmatteo wrote: ↑Tue Dec 29, 2020 1:22 amCan you try to increase the value of boxcutmin from 2 to e.g. 4?
We found some difference when comparing Abinit DFPT phonons with phonopy finite difference method with Abinit forces and we managed to make the phonopy results agree with DFPT by increasing boxcutmin.
BTW: Are you using ADDGRID=True (https://www.vasp.at/wiki/index.php/ADDGRID) in your Vasp calculations?
Yes, ADDGRID=True is used in vasp calculations.