3D structure of amorphous SiO2

Materials Project
1

Hi,

How to use materials project web site to get amorphous SiO2 structure? I did search SiO2 in Materials Explorer. The search result is so many materials ID (321). Most of them have crystal structure. How to get amorphous SiO2 structure? Is there a way to provide me with best solution for this search?

Best
LK

2

Hey @leila_karami, the easiest way is using our python client to download documents and filter based on whether they come from an amorphous calculation. This provenance information isn’t stored for every material.

There are many caveats when trying to represent an amorphous material as a small ordered cell. The resultant structure could be phase separated, or not accurately reflect the bulk amorphous material.

With those caveats, the following code snippet uses our client to retrieve all materials that have an SiO2 formula unit, then retrieves their provenance to see if any were tagged as derived from an “amorphous” structure.

The final material IDs, which may be representations of amorphous SiO2, are in amorphous_si_o2_mpids.

I found 7 possibly amorphous SiO2 entries in MP 
["mp-1244945", "mp-1244965", "mp-1244968", "mp-1245026", "mp-640917", "mp-6930", "mp-6945"]

from mp_api.client import MPRester
from pymatgen.core import Composition

target_composition = Composition({"Si": 1, "O": 2})
with MPRester() as mpr:
    si_o_mpids = [
        doc.material_id
        for doc in mpr.materials.search(chemsys="Si-O", fields = ["material_id","composition_reduced"])
        if doc.composition_reduced == target_composition
    ]
    si_o_prov = mpr.materials.provenance.search(material_ids=si_o_mpids)
amorphous_si_o2_mpids = [doc.material_id.string for doc in si_o_prov if any("amorphous" in tag.lower() for tag in doc.tags)]

There’s also a database of non-crystalline materials which was recently published via MPContribs.

Using similar code to extract entries: 
with MPRester() as mpr:
    contribs_data = mpr.contribs.query_contributions({"project": "amorphous_diffusivity"},paginate=True)
    contribs_si_o2_entries = [entry for entry in contribs_data["data"] if Composition(entry["formula"]).reduced_composition == target_composition]

I found only one possibly amorphous SiO2 entry

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