Unresolvable Identifier

arXiv:2604.20277 · detector doi_compliance · cross_source · 2026-05-20 02:07:54.996154+00:00

critical doi_compliance unresolvable_identifier

Identifier '10.1073/pnas.2115703118(2021' is syntactically valid but the DOI registry (doi.org) returned 404, and Crossref / OpenAlex / internal corpus also have no record. The cited work could not be located through any authoritative source.

Paper page Integrity report arXiv Try DOI

Evidence text

Wu, M. & Li, J. Sliding ferroelectricity in 2D van der Waals materials: Related physics and future opportunities. Proc. Natl. Acad. Sci.118, e2115703118, DOI:10.1073/pnas.2115703118(2021)

Evidence payload

{
  "arxiv_id": null,
  "checked_sources": [
    "crossref_by_doi",
    "openalex_by_doi",
    "doi_org_head"
  ],
  "doi": "10.1073/pnas.2115703118(2021",
  "raw_excerpt": "Wu, M. & Li, J. Sliding ferroelectricity in 2D van der Waals materials: Related physics and future opportunities. Proc. Natl. Acad. Sci.118, e2115703118, DOI:10.1073/pnas.2115703118(2021)",
  "ref_index": 8,
  "verdict_class": "cross_source"
}