Materials Project Database Release Log

We’ve released a new revision of the Materials Project database as part of a major overhaul of our software infrastructure. This enables us to continue to build new properties and deliver them to you, the material science community, at an accelerating pace. This has also caused some growing pains as we fix bugs we created in building our new infrastructure from scratch.

Many of our users have reported bugs, and we are very grateful for that. We’re making great strides in being as transparent as possible so everyone knows what is changing. As part of this, we’ve settled on a monthly release schedule including an announcement that informs everyone on what has or has not changed.

v2019.11

  • Introduced 3,971 new materials
  • Amorphous materials added with amorphous tag
  • Added theoretical which is True when the material matches no known experimental structure from ICSD
  • Fixed several inconsistency bugs for band_gap, piezo tensors, elastic warnings, and total magnetic moment.

V2019.05

  • Introduced a new deprecated field to materials. By default the website and API only search for materials that are not deprecated: {“deprecated”: false}.
  • Deprecated 15,000 and added 3,600 new materials. We will be recomputing the deprecated materials to fill these spaces back up. Some of these new relaxations may end up matching current materials, so the total number of materials is not guaranteed to be the same as in V2019.02.
  • Fixed an issue with sandboxes not properly building the whole hull. Previously, only the sandboxed chemical systems were being recalculated for energy_above_hull searches

V2019.02

  • Added over 47,000 new materials from orderings of disordered ICSD as well as compounds from the Pauling File
  • Finalized enforcing symmetry on piezo tensors
  • Moved third order elastic data to elasticity_third_order so that people are not swamped by the mountain of information associated with it.

V2018.12

  • Adjusted the mp-id naming scheme to fix “mvc” ids taking over old mp-ids.
  • Fixed piezoeletric max_direction to be a miller index rather than a unit vector.

V2018.11

  • Changed the grouping of magnetic materials to aggregate all magnetic orderings of a given material into a single material-id, and report the lowest energy ordering
  • Fixed incorrect calculation and display of polycrystalline dielectric constants
  • Fixed labeling of all materials as high-pressure. Note we’re parsing ICSD tags for this labeling so while some materials may not conventionally be considered high-pressure, a single matching ICSD entry can tag a material as such. We would love to hear comments on how we could better tag high-pressure materials
  • Begun enforcing the symmetry of the structure on piezo tensors. In general, this reduces the expected piezo value.
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We’re onto to the second monthly release of our database. We continue to fix a lot of issues you’ve all flagged for us. Thank you for finding bugs. There are only a handful of developers in the Materials Project and we benefit immensely from the community. Please keep sending in bugs as you find them.

It’s also been pointed out that Materials Project has been running slowly for a number of people. We’ve had a sudden increase in load, likely due to the number of talks at MRS 2018 referencing Materials Project data for machine learning. We’re are working on scaling the website to cope with the load.

V2018.12

  • Adjusted the mp-id naming scheme to fix “mvc” ids taking over old mp-ids.
  • Fixed piezoeletric max_direction to be a miller index rather than a unit vector.
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We’re onto to our third release of our database which is coming a bit late, but we have a good excuse. Our dogs ate our database.

In reality, we’ve been preparing a major increase in the material count by a little over 47,000 new materials. These come primarily from finding orderings of many disordered structures in the ICSD as well as some structures originally from the Pauling files. We continue to use our structure matcher to ensure we’re not duplicating materials so the current set should offer good coverage of both the ICSD and Pauling files.

We’re onto the V2019.05 release of the MP Database. The last release (V2019.02) introduced a number of new compounds, but unfortunately also highlighted a validation issue for us that has actually been present for a while now in MP. The issue was this: Most of our structure optimizations show very small changes in the input volume, keeping the k-points consistent. However, for a number of new compounds, the volume change was significant – greater than 50% – which drastically changed the k-points necessary for proper coordinates and energies. These outlier compounds were not being caught before.

Rather than just removing them completely, we’ve built a deprecation tag to softly “remove” such materials from searches and phase diagrams. Exploring MP via the website will not show these materials, but you can still find them by ID via the API and by direct links; if a material was referenced in a publication, its data is still accessible.

It’s been a long time since we released an updated database. We’ve been making a lot of changes in the backend to get ready for a whole new API and what will eventually be a completely new website. This will address several issues we’ve had with expanding the dataset and potentially moving some of our data to AWS to minimize downtime.

Major Changes
This latest release V2019.11 introduces 3,971 new materials. Of particular note is “amorphous” materials we’ve computed as part of our Synthesizeability Skyline. You can search for these by an “amorphous” tag.

As previously announced, we’re tagging materials as “theoretical” if we don’t have an experimental ICSD ID. In the future, we’re adding the Pauling File IDs and Crystallography Open Database IDs which will all affect this tag.

Bug Fixes

  • Fixed elasticity warnings to properly show up in the materials doc
  • Fixed an issue with piezo tensors which were parsing VASP’s voigt notation expecting conventionla voigt notation
  • Several bandgaps were being incorrectly reported from structure optimizations rather than static calculations; this inconsistency should be fixed.
  • Updated magnetism to be consistently from structure optimizations for now
  • Fixed volume and NSites to corresponding to the same cell in search and materials detail page

2019-11-21 During deployment of the new v2019.11 database, there was temporary issue with generating interactive phase diagrams leading to incorrect formation enthalpies for a small number of chemical systems. This has now been fixed. Data presented on the materials detail pages was unaffected by this issue.

2019-12-04 We are aware of an on-going issue with the reported energies above hull on the materials detail pages. We will update this thread when a fix has been fully implemented and with further details.

Until this issue is fully resolved, correct energies above hull can be retrieved using pymatgen as follows:

from pymatgen import MPRester
from pymatgen.analysis.phase_diagram import PhaseDiagram

with MPRester(YOUR_API_KEY_HERE) as mpr:
    # replace with your elements and mp-id of interest
    entries = mpr.get_entries_in_chemsys(['Li','Co', 'O'])
    entry_of_interest = mpr.get_entry_by_material_id('mp-19128')

phase_diagram = PhaseDiagram(entries)
e_above_hull = phase_diagram.get_e_above_hull(entry_of_interest)

print("e_above_hull", e_above_hull)

If you have not previously used pymatgen, it is a Python code and can be installed using pip install pymatgen or conda install --channel conda-forge pymatgen and your API key can be found on your Dashboard when logged in.

2019-12-05 The issue mentioned in 2019-12-04 has now been addressed, however approximately 7% of materials saw errors in their reported energies above hull of greater than 0.05 eV/atom. Values calculated via pymatgen or via the phase diagram app on the website during this time were correct, while values reported on the materials details page and via the e_above_hull API key were incorrect.

We encourage users who accessed convex hulls from the website between the latest database release and 2019-12-05 to re-check any values obtained from the website.

We apologize for the error, and will be incorporating additional checks into our automated testing to prevent similar errors in the future.