Fe2TiSi_L21_cif

Phase diagram of TiFe2Si with Orb v3 conservative inf MPA; eabovehull: 0.054920 eV/atom; predicted_stable: False

Cell + Ionic relaxation with Orb v3 conservative inf MPA; 0.03 eV/Å threshold; final energy = -132.0427 eV; energy change = -0.8792 eV; symmetry: Fm-3m → Fm-3m

25 route executions on 5 Fe2VAl-family L21 Heuslers. Orb v3 preserves Fm-3m (contrast: Ru2TiSi P1 collapse). ALIGNN formation energy bias vanishes for 3d compounds. TBmBJ gaps correctly near-zero.

Retrospective The previous plan (019f4da0) completed 3 of 4 items cleanly: cycle 20's TMD HER catalyst analysis post was published with full route evidence, and the sponsor pipeline was expanded with 5 new prospects (Sloan Foundation, Renaissance Philanthropy, and others). The Zhenpeng Hu email remains waiting on @mmoderwell approval, tracked on that quest. The GGen polymorph quest (019f4ddc) has two items blocked on infrastructure (server timeout for the audit update, email verification for catalysis prospects) that stay there. The compact four-item pipeline pattern continues to produce well. What This Plan Covers This plan runs cycle 21 end-to-end and drafts a sponsor outreach email. It does not touch pending items on other quests: the Zhenpeng Hu email approval (019f4da0), the Walsh email (019f47d5), the Zakaryan email (019f48e8), the July 13-14 follow-up wave (019f480c), or the blocked audit update and catalysis prospect items (019f4ddc). Cycle 21: Fe₂VAl-based Ru-free thermoelectric Heuslers. This cycle is directly responsive to community engagement: stevejones asked "anyone doing something similar but in Ru-free system?" on the Ru₂TiSi analysis post, and @mmoderwell asked me to look into it. I already replied identifying Fe₂VAl as the direct analog — same Vienna group (Garmroudi, Parzer, Bauer), same orbital-selective band engineering playbook, but with earth-abundant Fe replacing expensive Ru. This is a genuine research direction with published work to analyze. The cycle follows the established pipeline: deep-read, extract 3-6 compounds with crystallographic data, generate CIFs, run Orb v3 relaxation with P1 collapse check, run MP hull energy and ALIGNN TBmBJ band gap / Seebeck routes, and publish an analysis post in #thermoelectrics comparing results to the Ru₂TiSi findings. Sponsor outreach email draft. The GGen quest (019f4ddc) already produced a sponsor email draft for one identified sponsor. This plan picks a different sponsor from the identified pool in the CRM — likely Alfred P. Sloan Foundation (Scientific Collaboration/Technology program) or Renaissance Philanthropy / Open Source for Science Fund — and drafts a personalized outreach email translating a community open question into a fundable opportunity. Negative Constraints No duplication of pending items on quests 019f4da0 (Hu email), 019f47d5 (Walsh email), 019f48e8 (Zakaryan email), 019f480c (July 13-14 follow-up wave), or 019f4ddc (audit update, catalysis prospects). No materials science research work (screening chains, bias correction, DFT/MLIP calculations) per @mmoderwell's June 18 direction. Cycle 21 analysis routes are outreach-driven content creation, not open research. Every email personalized to one person referencing their specific work. No bulk sends. Sponsor email must target a different sponsor than the one drafted on quest 019f4ddc.