Hello. I want to obtain the energy above hull of a new material which is not in MP.
So I want to get energy of other phases in the chemical space from MP, then add this new phase(energy calculated by myself) into the phase diagram and obtain this new material’s energy above hull.
So the version of my pseudopotential should be same as the version used in MP.
But I fould that the MP’s pesudopotential cannot be download from VASP website, because the version used in MP is older than the oldest version I can find in VASP web(for example, Gd’s potential is 2002 version in MP but it can not be found in VASP web), is that right？How can I get the pesudopotential whose version is same as that used in MP?Or is there any other way to obtain the reliable energy above hull?
Hi @Zhewen_Zhu, the TITELs in VASP’s POTCAR don’t necessarily reflect the year a pseudopotential was updated. For example, the PBE 64 pseudopotentials were just released this year, but the Cs_sv POTCAR (updated in this set) still has a PAW_PBE Cs_sv 25Jan2019 TITEL.
The PBE GGA calculations on MP use the “PAW POTCAR files: LDA & PW91 & PBE” pseudopotentials (snapshot 06-05-2010).
If you want to do MP-compatible calculations, for which you also need consistent settings for ENCUT, k-point density, etc. I strongly recommend using either pymatgen or atomate2:
pymatgen.io.vasp.setsallows you to make VASP input files using MP’s default settings via MPStaticSet and MPRelaxSet (see here)- The
MPGGADoubleRelaxStaticMakerworkflow fromatomate2.vasp.flows.mpis used to generate all phase diagram data on MP
Hi,@Aaron_Kaplan. Thank you very much for your detailed answer !!!
But I still have a question:
For example, I found the raw calculation file for ‘Gd2Zr2O7’ in NOMAD (NOMAD), the pseudopotential of Gd used in MP’s calculation is ‘PAW_PBE Gd 08Apr2002’. However, the pseudopotential of Gd in “PAW POTCAR files: LDA & PW91 & PBE” pseudopotentials (snapshot 06-05-2010) " is ‘PAW_PBE Gd 23Dec2003’. So, it seems that they are two different Gd’s pesudopotential version. Why these two versions are different?
(This problem also exist for the element Zr, Ge, Ce, Eu and so on)
I’m looking forward your answer, thank you!
Hi @Zhewen_Zhu,
Confirming what you observed. It appears that some of the POTCARs were updated in place without releasing a new version of the POTCAR library.
For now, I recommend using the PBE 54 pseudopotentials for your calculations. That’s the current default in the atomate2 version of our r2SCAN workflow. The Gd POTCAR used there has TITEL PAW_PBE Gd 23Dec2003
As long as you keep formation energy calculations consistent (compound and elemental references computed with the same POTCAR set), you should be able to add new compounds to the existing phase diagram without much loss of accuracy
@Zhewen_Zhu Just wanted to add that the calculation you found on NOMAD is for task mp-1371228 which does not appear to be the blessed task for this material anymore. You can find more calculation details for the new blessed task mp-757233 on the according calculations page.