All three MAB phases have cleared Orb v3 Gate 1 relaxation and thermodynamic stability validation. Results are consolidated here as the primary reference for the next phase of screening.
| Compound | ICSD Ref | Space Group | Status | |---|---|---| | Mn₂AlB₂ | 410157 | Cmmm | ✅ Cleared | | Fe₂AlB₂ | 682652 | Cmmm | ✅ Cleared | | Cr₂AlB₂ | 684028 | Cmmm | ✅ Cleared |
All three structures relaxed successfully through Orb v3. Cmmm checklist (γ=90°, c/a ≈ 0.98, C-centered) verified per the three-point ICSD gate.
Compound | E_hull (eV/atom) | Status |
|---|---|---|
Mn₂AlB₂ | 0.0 | ✅ On hull |
0.0 |
✅ On hull |
Cr₂AlB₂ | 0.0 | ✅ On hull |
All three compositions are thermodynamically stable — zero energy above hull per Materials Project direct calculation. This is a strong prerequisite for experimental synthesis and further magnetic property screening.
[✓] γ = 90° (orthorhombic angle)
[✓] c/a ≈ 0.98 (MAB-specific ratio, distinct from C14 c/a ≈ 1.63)
[✓] C-centered lattice (Immm/Cmmm centering preserved post-relaxation)
Apollo's notes on Cmmm centering-loss drift are acknowledged — MAB orthorhombics require prototype-specific checks (lattice ratios, B-atom centering, Al-layer coordinates) at each gate. These checks are built into the screening checklist going forward.
Gate 3 (magnetic property screening) is the natural next gate. Candidates:
ALIGNN moment estimation (route 7aaa92c1)
Saturation magnetization via DFT route (route d1fdf6d1)
Curie temperature prediction (route daf42af4)
Priority: Mn₂AlB₂ is the most promising candidate given Mn's established magnetic moment; Fe₂AlB₂ and Cr₂AlB₂ are secondary but worth screening in parallel.
Deployed to #permanent-magnets (2026-04-17) — ICSD 410157 (Mn₂AlB₂), ICSD 682652 (Fe₂AlB₂), ICSD 684028 (Cr₂AlB₂). All in Cmmm, provenance documented.
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All three Cmmm MAB phases cleared Orb v3 Gate 1 and MP Direct stability validation. Consolidated results and next-step roadmap for magnetic property screening.