Hello all,
I am a Quantum espresso user and is aware of Boltztrap. But Boltztrap do not give us lattice thermal conductivity.!!! I found another code ShengBTE which gives this value but somehow didnot fully understood how to run it!!! anyone can help with this???
I am looking forward for yours kind response.
Thanks in advance
First you need to compute the second order interactomic force constants (phonons) which can be done with phonopy.
Then you need generate the displacements corresponding to the calculation of the third-order force constants (phonon-phonon processes). One you have the second- and third-order force constants you can use ShengBTE to solve the BTE for phonons in that way.
Depending on the material you may need to compute the dielectric tensor and born charges.
Hope it helps, but the code has some great examples tht
... that you can follow along and would give you a pretty good idea to how to use the code.
Steps are as follows:
1. create supercell by using phonopy with suitable size, for example 222. After then run Quantum espresso to calculate force on each atoms for all displacements and then run phonopy again to generate second order force constants file. You need to keep this file into the folder where you will run shengbte.
2. create displacements (supercell size can be different from 2nd) at least up to third order by using third_order_pwscf/qe.py. this will create large number of files that you need to run by QE. Write python script to copy QE input header into each files and then run all scf file sequentially to calculate forces on each atom. Run again third_order_pwscf/qe.py with reap option to calculate third order force constant. You need to keep this file into the folder where you will run shengbte.
3. Run QE phonon calculation with epsilon true option to calculate born charge and dielectric constant. these parameter are required to write 'control' file.
4. Using all information, write 'control' file. You need to keep this file into the folder where you will run shengbte.
4. Now run shengbte. Note shengbte requires huge amount of RAM.
Hope you will be successful in your mission!
Enamul Haque Dear sir, could you provide me some example CONTROL for ShengBTE calculation.I already calculated 2nd and 3rd force constants by ALAMODE packages and phonopy.I already installed and tested examples in SHENGBTE.But, I don't understand fully for control file.Best regards
How is the second- and third-order force constants calculated? I am new in this so I have tried to use 'thirdorder_espresso.py' following the attached guide but i got stuck at some point; i dont understand how this command can be changed to run with QE. and what to place in place of the 3RD.POSCAR., INCAR, POTCAR, KPOINTS, and runvasp.sh.
https://drive.google.com/file/d/1Td2WYtmWaX3nVtsZ2_4Pidd9Dryn5sAg/view?usp=sharing
================================================================
```bash
for i in 3RD.POSCAR.*;do
s=$(echo $i|cut -d"." -f3) &&
d=job-$s &&
mkdir $d &&
cp $i $d/POSCAR &&
cp ~/vaspinputs/INCAR ~/vaspinputs/POTCAR ~/vaspinputs/KPOINTS $d &&
cp ~/vaspinputs/runvasp.sh $d &&
(cd $d && qsub runvasp.sh)
done
```
================================================================
Hi Makumi,
You need change poscar to scf and place another bash script writing your qe command in the vaspinput folder. You must write a script also to copy input header to all supercell files.
Best wishes.
Hi Aung,
The CONTROL file contains structural paramters, non-analytical term correcting parameters, crystal orientaions, temperature at which kl need to be calculated,Gaussian broading factor, and etc. For example, you need to write total number of atoms and their types, positions, in the unit cell you used in force calculations along with lattice vectors in nm.
Best Wishes,
Can anyone please tell me , what should be the INCAR file to run vasp of thirdorder generated cases?
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