Rare-earth silicide qubit substrate and integrated cryogenic quantum computing system

Rare-earth transition-metal silicide compounds of the RE-T-Si family are emerging as candidate materials for qubit substrates, electrodes, and couplers in superconducting quantum processors, and this portfolio staked out the device and system integration claims before the materials literature drew commercial attention. The core protection is a system claim — not a composition claim — covering a quantum-device article comprising a screening-validated RE-1:1:1 silicide integrated with a superconducting qubit, resonator, or coupler, together with the full cryogenic system that surrounds it: the cryocooler or dilution-refrigerator stage that cools the assembly below the material's ordering or transition temperature, plus the read-out electronics. That system boundary is the claim's commercial lever, because it captures the assembled quantum stack at the point where substrate and coupler choices propagate across an entire processor rather than at any individually swappable component. The timing rationale is structural. Quantum-processor developers are now scaling qubit counts aggressively, and as they do, the substrate and interface-layer materials become a primary coherence and yield variable. The incumbent materials — silicon, sapphire, and niobium — carry well-documented loss mechanisms and are largely composition-locked by prior art. A system claim anchored to a computationally validated alternative silicide substrate, filed while that integration pattern is still uncrowded, positions the holder at a juncture where every additional qubit that gets built using that configuration adds to the royalty base. The addressable market estimate of $5B+ reflects the cumulative value of quantum computing hardware shipments as the industry scales; the system and device-use claim structure means value accrues at the assembled-system level, not at a commodity material layer.

Each candidate is validated by multiple independent machine-learning interatomic potentials. A material advances only when the engines agree on phonon (dynamic) stability — disagreement is surfaced, not hidden.

The claimed article uses a member of the RE-T-Si (rare-earth, transition-metal, silicon) ternary silicide family, selected through a validated computational screening pipeline, in layered crystal structure types — including ThCr2Si2-derived and PbFCl/CeFeSi-type geometries — deposited as a thin film and integrated as a qubit substrate, electrode, or coupler alongside a superconducting qubit or resonator element. Five concrete compound embodiments were identified through the screening process: CeCuSi, CeNiSi, CeRuSi, LaRuSi, and NdNiSi. The system claim adds the surrounding cryogenic infrastructure — a cryocooler or dilution-refrigerator stage operating below the material's ordering or transition temperature — and the read-out electronics, defining a complete integrated quantum stack. Computational validation was conducted using four independent machine-learning interatomic potentials, the cross-potential consensus framework that Lattice Graph's rare-earth silicide superconductor candidates portfolio applies as its primary stability gate. The selected member returned a majority-stable verdict across all four engines, meaning no imaginary phonon modes were flagged by the preponderance of potentials — a result that reflects genuine cross-method agreement on dynamic (lattice) stability rather than an artifact of any single potential's training set. A freedom-to-operate whitespace prescreen was also run, scoped specifically to device-use rather than composition, before the claims were structured. The physics motivation for these silicides as qubit substrates is straightforward: superconducting qubit coherence times are acutely sensitive to substrate dielectric loss and to interface-driven two-level system defects. The RE-T-Si layered silicides offer a distinct structural and electronic profile from the conventional Si/sapphire/Nb substrates — including, in several members, intrinsic superconducting or magnetic ordering that could serve an active coupler or electrode role rather than merely a passive substrate role. That functional duality is what elevates the claim from a substrate substitution to a system-level integration strategy. What the computational work establishes is structural viability and a stable phonon landscape; what remains to be established experimentally is the dielectric loss tangent, interface quality, and ultimately the qubit coherence in an integrated stack — the properties that will determine which of the five candidate compounds advances to fabrication.

The addressable market for quantum computing hardware is estimated at $5B+ and growing as government and corporate quantum programs move from single-digit qubit demonstrations to processors designed for fault-tolerant operation at scale. The primary buyers of this system claim are quantum-processor developers — well-capitalized hardware companies and national laboratories whose substrate and coupler material choices are made at the processor-architecture level and then locked in across production runs. This is not a consumables market; it is a high-value, low-unit-volume market where per-system or per-processor royalties reflect the integrated value of a full quantum stack rather than the commodity cost of a thin-film layer. The royalty logic for a system claim of this scope favors a per-processor or per-system running royalty, potentially layered with integration milestones triggered when a licensee qualifies a silicide substrate or coupler in a production-grade cryogenic system. Because the claim reads on the assembled article and the full cryogenic system — not on the material in isolation — the royalty attaches to the highest-value unit in the supply chain, an assembled quantum processor in its cryogenic environment, rather than to an upstream wafer supply. The bifurcated claim structure (device article plus integrated system) also supports layered licensing: a component supplier integrating the silicide as a substrate or electrode film falls under the article claim, while an OEM shipping a complete cryogenic quantum system falls under the system claim. As qubit counts scale and system-level shipment values rise, the system-level claim becomes progressively more valuable. The $5B+ figure should be understood as a market-sizing estimate spanning the near-to-medium term build-out of the quantum-hardware industry; the capturable fraction through licensing or acquisition depends on how broadly the selected silicides are adopted and how quickly the empirical validation gates are cleared.

quantum-substrate/system whitespace tied to method-validated members

system/device-use claim to a method-selected material; not a composition claim

The natural acquirers or licensees are quantum-processor developers — companies and national labs actively building superconducting qubit systems at scale — for whom substrate and coupler material choices are made at the architecture level and propagate across an entire device generation. These are well-funded strategics for whom a system claim covering a computationally vetted alternative substrate material is both an offensive tool (blocking rivals from using the same integration configuration) and a development option (licensing in a validated candidate to test in their own fab process). A leading quantum-hardware company is the strongest acquisition candidate: owning the system claim together with the upstream computational selection method secures the validated silicide shortlist, the device-article claim, and the integrated-system claim in a single transaction, denying rivals access to the same lane. A system integrator or cryogenics OEM shipping complete quantum systems is a natural licensee under the system claim. License-versus-acquire logic hinges on exclusivity: a developer seeking to lock the integration point for a full processor generation would pursue exclusive field-of-use rights or outright acquisition; a developer merely hedging substrate options for a single architecture would license non-exclusively at a lower commitment. In either case, the five concrete compound embodiments — CeCuSi, CeNiSi, CeRuSi, LaRuSi, NdNiSi — give the counterparty specific candidates to evaluate in their fab process immediately.

The most significant risk is empirical: the transition temperature for the selected member is based on computational screening only and has not been experimentally validated. More critically, the properties that actually determine qubit substrate performance — dielectric loss tangent, two-level-system defect density at the silicide/qubit interface, and interface-driven decoherence — are entirely unmeasured here and are precisely the properties on which many candidate substrate materials have failed when moved to integrated testing. Computational phonon stability is a necessary but far-from-sufficient condition for qubit substrate viability; a structurally stable silicide can still fail as a substrate due to surface chemistry, film growth defects, or intrinsic loss mechanisms that no ML potential predicts. The practical de-risking path is the one the asset's own proof gates define: fund an integrated cryogenic quantum-system test vehicle with measured qubit-coupling characterization. That program converts a configuration claim with computational provenance into a demonstrated integrated result, transforming the asset from a design-around-able option into a validated platform. The timeline and cost of that program are consistent with what quantum-hardware developers already budget for substrate qualification, so the empirical gap is not structurally prohibitive — but a buyer should enter any transaction with clear expectations that the system claim's commercial ceiling is gated by experimental results that are not yet in hand.