Extract data for particular structure

pymatgen
1

Hi,

Can someone let me know how can I extract data for particular structure(e…g Cubic only) within 1 eV band gap using pymatgen?

Thanks and regards

Sandeep

2

Hi Sandeep,

If I understood your question correctly this question is regarding the MAPI, not pymatgen.
You can query for these materials using MPRester by specifying:

with MPRester("your-mapi-key") as m:
    data = m.query(criteria={'spacegroup.crystal_system': {'$eq': 'cubic'},
                            'band_gap': {'$lt': 1.0}
                            },
                            properties=['material_id'])

This returns the properties you specify for materials that are cubic and have a band gap less than 1 eV.

Best,
Peter

3

Dear Peter,

Thank you very much for your reply. It works well. I have one more query about the direct and indirect band gap semiconductor materials . I mean how can extract the data for direct and indirect band semiconductor materials separately ?

Thanks and kind regards

Sandeep

4

Glad it works! I think you can specify that by adding 'band_gap.is_direct': False for indirect and True for direct.

-Peter

5

Dear Peter,

Thank you for reply. I tried with ‘band_gap.is_direct’: False in mp.query but it does not work.
mp.query(criteria={“band_gap”:{’$gt’:0.4,’$lt’:1.0},
‘spacegroup.crystal_system’: {’$eq’: ‘tetragonal’}, ‘band_gap.is_direct’: False}

Could you tell me where I did make mistake?

best regards

Sandeep

6

Oh, I think my previous post was wrong.
This should work though: 'band_gap.search_gap.is_direct': False
-Peter

7

Dear Peter,

Thank you! It works now. Could you please let me know the source where I can find the terminology of mp-query?

best regards

Sandeep

8

Great! Glad it worked. You can find the information here: https://docs.materialsproject.org/open-apis/the-materials-api/ and https://github.com/materialsproject/mapidoc
Good luck with your research!
-Peter

9

Dear Peter,

Thanks a lot for your kind cooperation. I have one more query. Is it possible to extract the refractive index only using diel task?

best regards

Sandeep

10

Yes, that’s possible as you can see in the diel folder in the second link of my previous post. However, I believe only about 1000 materials in the MP have that property calculated. Some details about these calculations can be read here: https://materialsproject.org/docs/calculations#dielectric
-Peter

11

Dear Peter,
If we query for diel, it contains a tensor, dielectric constant, refractive index, and recognized potential. How can we extract the data for dielectric constant or refractive index only with the help of diel?

Thanks and regards
Sandeep

12

Oh, yes, of course: diel.n

13

Thank you dear Peter!

regards

Sandeep

1 Like
14

Dear Peter,
Can we set a range of band_gap in the query?

15

Yes, what Sandeep wrote above should work: "band_gap": {'$gt': 0.4,'$lt': 1.0}

-Peter