MatCore and the vocabulary

MatSci-SAM publishes vocabulary concepts and MatCore metadata elements.

Terms and classification tags are SKOS concepts. Topics classify definitions, and facets classify terms. MatCore elements are fields for computational dataset metadata (Greenberg et al., 2025).

MatCore profiles

Greenberg et al. present MatCore as a two-tier metadata model for computational materials datasets. The Minimal MatCore Metadata profile provides fields common to every dataset. The second tier adds fields for density functional theory (DFT), classical molecular dynamics, GW/BSE, machine learning, and derivative methods (see Figure 1). MatSci-SAM represents the Minimal and DFT profiles from the preliminary arXiv:2502.07106v1 snapshot dated February 10, 2025.

The Minimal profile contains 18 elements. The 13 required elements are creator, title, date, description, material, calculation-type, simulation-conditions, method, software-code, matcore-version, matcore-id, matcore-date, and license. The five optional elements are disclaimer, software-files, Source-citation, doi, and funding (see Figure 3).

The DFT profile is the optional second tier for density functional theory. Its three required elements are xc-functional, potential, and basis-set. The six optional elements are calculation-physics, k-points, k-smearing, Self-consistent-field-convergence, state-occupations, and relaxation-convergence (see Figure 5).

MatSci-SAM representation

MatCore metadata presents the 27 element definitions and one synthetic DFT example. The catalog preserves the source spelling of each key and its requirement marker. The descriptions are concise paraphrases of the source tables.

MatSci-SAM assigns each element a normalized identifier under /metadata/matcore# and publishes it as an rdf:Property with an English label and comment. The RDF also records the source key, requirement status, and profile membership. The Minimal and DFT profiles are matsci:MetadataProfile resources, and a dcterms:Standard resource identifies the source snapshot.

The MatCore element set is available as a named graph at /graphs/matcore and as part of /dataset.ttl.

Vocabulary and Dublin Core

MatCore elements identify fields in computational dataset metadata. Vocabulary terms identify materials science concepts. MatSci-SAM connects the material element to the vocabulary with rdfs:range.

<…/metadata/matcore#material> a rdf:Property ;
  rdfs:label "Material"@en ;
  rdfs:range <…/vocabulary> .

This range names the default MatSci-SAM concept scheme at /vocabulary. Community vocabularies have separate scheme IRIs at /vocabulary/{community}.

The MatSci-SAM RDF layer also maps seven general MatCore elements to Dublin Core.