Stage 3 bounded Tc predictions and controls

2D Layered Ternary Superconductor Discovery Goal: Discover novel layered ternary compounds with superconducting Tc significantly above the current 2D SC ceiling (NbSe₂ ≈ 5 K monolayer), targeting Tc ≥ 15 K at ambient pressure — the threshold for practical device integration with TMD semiconductors (WS₂, MoS₂) via CVD-compatible synthesis. Why this matters: No known 2D superconductor exceeds ~6 K. A layered ternary chalcogenide/pnictide with Tc ≥ 15 K would be first-in-class for superconducting interconnects and Josephson junctions integrated with 2D logic. Pipeline | Stage | Tool | Description | Deliverable | |-------|------|-------------|-------------| | 1. Scout | GGen /ggen/scout | Screen element substitutions on layered templates. Max candidates per system: ≤ 50 (route limit parameter). | Ranked element families by hull distance + symmetry preservation | | 2. Explore | GGen /ggen/explore | Deep generation for top 3–5 ternary systems from Stage 1. | Relaxed CIFs, phase diagrams, stability ranking | | 3. Validate | 3DSC cross-check + DFT | Predict Tc for top candidates, validate against experimental benchmarks. | Ranked shortlist with predicted Tc | | 4. Synthesize | Feasibility assessment | CVD/MOCVD pathway analysis for top 5 candidates. | Synthesis recommendations | Target Structural Families (Stage 1 templates) CdI₂-type (P-3m1) — TMD backbone with vdW gap. M–X₂–X stacking. NbSe₂, TaS₂ families. AlB₂-type (P6/mmm) — Honeycomb boride/nitride layers. MgB₂ prototype (Tc = 39 K bulk, highest ambient-pressure non-cuprate). ThCr₂Si₂-type (I4/mmm) — Iron-pnictide backbone. ~30 known SCs, Tc up to 38 K in Ba₁₋ₓKₓFe₂As₂. Scout-Stage Chemical Systems (priority order) | System | Template | X pool | Hypothesis | |--------|----------|--------|------------| | Nb-Se-{X} | CdI₂-type | chalcogens (S, Te, Bi) | Extend best-known 2D SC family | | Ta-{X}-S | CdI₂-type | 4d/5d TMs (Nb, Mo, W, V) | Isostructural TMD with heavier element | | Fe-Te-{X} | ThCr₂Si₂-derived | chalcogens (Se, S) | Iron-chalcogenide SC family | | Mg-B-{X} | AlB₂-type | main-group (Al, C, N) | MgB₂ analogs with ternary modification | Estimated compute: 4 systems × 50 candidates = 200 relaxations. Success Criteria ≥ 10 thermodynamically stable (hull ≤ 50 meV/atom) layered ternary candidates ≥ 3 candidates with predicted Tc ≥ 15 K ≥ 1 candidate with CVD/MOCVD synthesis feasibility Open Questions CVD precursor availability — @mmoderwell's WS₂/MoS₂ synthesis expertise relevant here Monolayer vs. few-layer Tc suppression — how much Tc degrades from bulk to monolayer for each structural family vdW gap engineering — intercalation or functionalization to boost Tc without breaking layer structure Current Status Stage 1 ready to launch. GGen scout route updated with parameter. Awaiting confirmation of parameter name/default from route update.