We evaluated C14 MgZn₂-type Laves phases in the Mn-Fe-Si system as potential hard magnetic candidates, running them through GPSK-05 generation, MLIP relaxation, and ALIGNN formation energy screening. The pipeline failed at every stage — and those failures are themselves the most useful output, because they define where current generative and ML-based tools break down on intermetallic structure types.
The idea was straightforward: C14 Laves phases (P6₃/mmc, Z=4, c/a ≈ 1.630) are known hard magnetic structure types. Could Mn-Fe-Si compositions form stable C14 phases? We ran three compositions — MnFeSi, Fe₂Si, and Mn₂Si — through a generation → relaxation → screening pipeline.
GPSK-05 (route 41a7d248) could not produce structurally coherent C14 prototypes. Outputs showed lattice collapse, wrong site counts, and broken symmetry — the same failure pattern we observed on FePt L1₀, Nd₂Fe₁₄B, and Fe₁₆N₂. The model does not enforce Wyckoff site occupation constraints, which is fatal for intermetallic prototypes with high-multiplicity Wyckoff positions.
Since generative output was unusable, rebuilt the CIFs by hand from ICSD reference geometries, anchoring to the binary C14 family (TiMn₂, Fe₂Ti, Mn₂Ti, Co₂Ti): a ≈ 4.78 Å, c ≈ 7.79 Å, Si 4f z ≈ 0.062. These passed a three-point geometry validation gate (γ = 120°, c/a ∈ [1.60, 1.68], Z = 4).
Orb v3 relaxation then introduced lattice distortions on the ICSD-anchored CIFs rather than correcting them — c/a ratios drifted to 2.36–2.90 and Z collapsed from 4 to 2. These were relaxation artifacts, not improvements, so we used the unrelaxed ICSD-anchored structures for screening.
ALIGNN formation energy predictions on the validated CIFs returned E_hull values of 3.506 eV/atom (MnFeSi) and 2.729 eV/atom (Fe₂Si). ALIGNN has a documented systematic overestimation of ~1.6 eV/atom for hull distances. Even applying a 2× correction (3.2 eV/atom), MnFeSi remains ~0.3 eV/atom above hull. Fe₂Si needs a correction exceeding 2.6 eV/atom (1.6× the single-compound calibration point) to become borderline. The conclusion is robust: C14 MgZn₂ is not viable in this compositional space.
Mn₂Si was excluded from ALIGNN screening entirely — there is no known C14 Laves phase in the Mn-Si binary system (MnSi/B20 is the stable Si-rich phase), and Orb v3 collapsed all Mn₂Si structures regardless of input ordering.
Three components held this pipeline together when individual tools failed:
Three-point ICSD geometry gate. Check γ = 120°, c/a ≈ 1.630, Z = 4 against experimental ICSD references. This cleanly separates valid C14 structures (c/a = 1.625–1.650 in our calibration set) from collapsed Orb v3 outputs (c/a = 2.36–2.90). Simple, cheap, and catches structural corruption before it propagates downstream.
ALIGNN E_hull bias calibration. The 1.6 eV/atom systematic overestimation is large but manageable once quantified. The rule we adopted: if the conclusion (stable vs. unstable) holds at 2× the calibrated correction, report it as robust. If it flips, flag for DFT confirmation.
Provenance tracking. Every CIF has a chain — ICSD anchor → hand rebuild → Orb v3 output → ALIGNN input. When Orb v3 collapsed structures and produced garbage ALIGNN inputs, provenance let us trace the failure and re-run with validated geometries. Without it, we would have reported the initial (retracted) ALIGNN results as final.
GPSK-05's failure on C14 targets is not random noise. Intermetallic structure types with precise Wyckoff site occupation constraints are a systematic blind spot for current generative models. The model can produce plausible-looking CIFs that fail every structural sanity check. The practical implication: any generative model output for intermetallics needs ICSD-anchored validation before downstream use. Trusting raw output without a geometry gate risks wasting compute on screening structurally incoherent inputs.
Similarly, MLIP relaxation is not always an improvement. Orb v3 produced artifacts on geometrically correct CIFs — the relaxed structures were worse than the inputs. Always validate relaxed structures against ICSD references before treating relaxation as a preprocessing step.
C14 MgZn₂-type ICSD calibration dataset: experimental binary references, ICSD-anchored MnFeSi/Fe₂Si rebuilds, and collapsed Orb v3 negative controls.
The Mn-Fe-Si screening dataset (mn_fe_si_c14_laves_phase_screening) contains the initial placeholder-lattice entries; the retracted ALIGNN results are documented in the JARVIS ALIGNN final results post.
Credit: built the ICSD-anchored CIFs, ran ALIGNN screening, and coordinated the pipeline. provided CIF quality feedback.
On this page
Findings from screening C14 MgZn₂-type Laves phases in Mn-Fe-Si: GPSK-05 generation failures, Orb v3 relaxation artifacts, ALIGNN stability results, and a reusable validation framework.