Quantum computing, as the commanding height of next-generation information processing, has long been constrained by material foundations—ideal qubits require long coherence time, scalability and addressability simultaneously, which existing material systems struggle to achieve. High internal stress sp²–sp³ hybrid carbon materials, with their unique structural design, provide a novel solution. This article systematically elaborates the material's multiple application potentials in quantum computer manufacturing: as an atmospheric "chemical pressure" platform for superconducting qubits; as a low-noise quantum integration substrate; as addressable quantum functional units; and a unique path for photoelectric joint measurement and control through built-in NV centers. This article aims to demonstrate that this material may become "single-crystal silicon of the quantum era"—an engineerable platform integrating quantum state generation, evolution, readout and thermal management.
Current mainstream quantum computing technologies (superconducting qubits, ion traps, photonic quantum, etc.) face structural bottlenecks despite showing superiority on specific problems: harsh dependence on atomic-level order and extreme environmental isolation severely limits scalability; wiring, readout and error correction costs grow exponentially with qubit count; inherently incompatible with real engineering systems (high power, strong noise). The philosophical essence is "engineering against nature's complexity" rather than leveraging it.
Meanwhile, nature contains many quantum systems that work stably in noise and disorder—quantum coherent energy transfer in photosynthesis, collective behavior in strongly correlated electron systems, many-body localization and chaos edge states. These systems do not pursue perfect isolation but rely on intrinsic structural protection. This suggests a third path different from "gate-model quantum computing" and "traditional brain-like computing"—using material systems with special intrinsic structure to form highly coupled, controllable coherent electron/phase systems at mesoscopic scale, as a physical information processor at the quantum-classical boundary.
High internal stress sp²–sp³ hybrid carbon materials are candidates born for this path.
This material achieves unique structure-function integration through chemically bonded endogenous stress.
2.1 Structural essence: sp²–sp³ atomic-level covalent interconnection
The material is sintered from sp³ hybrid carbon phase (nanodiamond skeleton) and sp² hybrid carbon phase (graphene, carbon nanotubes, etc.) via medium-low pressure (0.1–2.0 GPa) in-situ chemical reaction. Chemical bonding agents (B, Si, Cr, etc.) react in-situ at sp²/sp³ interfaces during sintering, forming atomic-level covalent bridge structures (e.g. Si-C, B-C, Cr-C bonds), building a continuous 3D interconnected network. The key distinction from traditional mechanical mixing or van der Waals stacking: sp² and sp³ carbon phases achieve "chemical welding" via strong covalent bonds rather than simple physical contact. This endows the material with diamond rigidity and graphene conductivity/thermal conductivity at macroscopic scale.
2.2 Core innovation: Locked high endogenous stress field
Interface regions contain sub-stable lattice distortion zones induced by covalent bonding, lattice mismatch and thermal expansion differences, forming long-term locked residual endogenous stress. Experimental measurement shows local residual compressive stress ≥ 5 GPa, preferably 15–60 GPa.
2.3 Macroscopic performance advantages
Thanks to the unique sp²–sp³ interconnected network, at room temperature: electrical conductivity ≥ 1×10⁶ S/m; thermal conductivity ≥ 500 W/m·K (preferably 800+ W/m·K); Young's modulus ≥ 500 GPa (preferably 600–700 GPa); stress stability >90% endogenous stress retention in accelerated aging tests.
3.1 Material dilemma of existing superconducting qubits
Current superconducting qubits (e.g. Transmon) are mainly built from Josephson junctions of aluminum, niobium thin films—core issues: limited coherence time, integration scale bottleneck, harsh operating environment (mK cryogenic). Meanwhile, high-temperature superconducting systems (e.g. hydrogen-rich LaH₁₀, H₃S) only exist stably under hundred-GPa external pressure, relying on diamond anvil cells with tiny sample size, completely unengineerable.
3.2 This material's unique positioning: "Chemical pressure vessel" at atmospheric pressure
The 10–60 GPa locked endogenous stress field provides a revolutionary solution: embed functional phases requiring high-pressure stability as guest materials in pores, interlayers or internal channels; the material's intrinsic endogenous stress field applies compression equivalent to high-pressure environment on guests, stabilizing their high-pressure phase structure and electronic states at atmospheric pressure.
3.3 Significance for superconducting qubits
If high-Tc superconducting phases (Tc>77 K) can be stabilized in this material matrix: operating temperature raised to liquid nitrogen range; intrinsic noise reduced (all-carbon non-magnetic environment, ¹²C isotope purification can eliminate nuclear spin noise); integration density increased, potential qubit nodes per chip greatly increased.
4.1 Natural carrier for Josephson junction networks
This material can form Josephson-junction-array-like natural structures through microscopic configuration design: intercalation (alternating nanodiamond and graphene layers); filling (nanodiamond or graphene filling carbon nanotube cavities, forming 1D confined coaxial heterostructures); distorted interface (sp²–sp³ contact interfaces have lattice bending, undulation or atomic-level covalent pinning points induced by chemical bonding).
4.2 Quantum computing significance of disordered Josephson networks
The material's network is statistically uniform but spatially disordered, with continuously distributed coupling strength, naturally large scale (10⁶–10⁹+ junctions). Such systems have nonlinear many-body dynamics, rich energy spectrum, chaos-localization transition behavior—ideal hardware carriers for "quantum reservoir" or "physical neural networks".
4.3 Moiré superlattice and flat band engineering
The material's endogenous non-uniform strain field can simulate and enhance moiré-diamond flat band effects in twisted graphene. By designing stress gradient distribution, induce high-density-of-states flat or quasi-flat bands near Fermi level, providing structural basis for strongly correlated electron state regulation.
As quantum chip integration increases, thermal management becomes a key bottleneck. Superconducting qubits typically operate at 10–20 mK, while control lines introduce significant thermal load.
This material combines sp³ skeleton's ultra-high thermal conductivity (>500 W/m·K) with sp² network's electrical function for "structure-heat dissipation-electrical" integrated design: in-plane rapid heat diffusion (sp² carbon phase can reach 2000+ W/m·K); vertical efficient thermal conduction (sp³ diamond skeleton 500–700 W/m·K); thermal matching with refrigerators (diamond thermal expansion coefficient close to silicon, silicon carbide). Research by Prof. Lü Jian's team at City University of Hong Kong shows composite phase diamond (CPD) has stable performance near absolute zero, achieving 1 mK temperature measurement resolution at <10 K.
Nitrogen-vacancy (NV) centers in diamond are star systems in quantum sensing—room-temperature spin quantum states, sensitive to magnetic/electric field/temperature/stress, laser spin polarization and readout (ODMR), long coherence time.
This material uses nanodiamond as sp³ skeleton; NV centers can be introduced in-situ during synthesis for integrated quantum functional units and intrinsic measurement capability: magnetic coupling read mechanism (magnetic field changes from superconducting current or localized electron states cause Zeeman shift of adjacent NV center energy levels); parallel read potential (NV center arrays can achieve spatially resolved readout via laser scanning); thermal management synergy (material's high thermal conductivity rapidly exports heat from optical readout).
Effective coupling requires precise NV center positioning near superconducting junctions (<50 nm), demanding precise control of NV center position and orientation in nanodiamond.
7.1 Unitized logical qubit definition
Use micro-nano etching to divide material into micron-scale matrix units. Each unit contains thousands of nano Josephson junctions, forming robust logical units through statistical averaging and secondary logic error correction.
7.2 Full-stack integration architecture
Compute layer: superconducting islands or coherent electron clusters in sp²–sp³ interconnected network; measurement layer: NV center arrays embedded in diamond skeleton; thermal layer: material's high thermal conductivity with external microchannel liquid cooling; interconnect layer: carbon nanotubes as quantum bus.
7.3 Process scalability
Material preparation is completed at medium-low pressure (0.1–2.0 GPa), achievable with spark plasma sintering (SPS) or hot pressing for gram to kilogram batch production.
High internal stress sp²–sp³ hybrid carbon materials, with their unique "chemically bonded endogenous stress" design, open a new technical path for quantum computer manufacturing. Core value is reflected at three levels:
At material level: achieves atomic-level synergy of diamond rigidity and graphene conductivity/thermal conductivity, while building an atmospheric "chemical pressure platform" equivalent to high-pressure environment through locked high internal stress field.
At structural level: through intercalation, filling, distorted interface microscopic configuration design, naturally forms Josephson-junction-like network as physical carrier for large-scale disordered quantum networks.
At system level: integrates quantum functional units, measurement capability (NV centers) and extreme thermal management, enabling "compute-store-read-dissipate" integrated full-stack quantum chips.
From "against nature's complexity" to "leveraging nature's complexity", from "external protection of fragile quantum states" to "internal material creation of silent, high-pressure quantum survival space". Whether the final realization is macroscopic long-range coherent superconductivity, topological qubits, or new paradigms of quantum emergent computing, this material will play a key role in quantum computing's journey from research to application. We believe high internal stress sp²–sp³ hybrid carbon materials based on the same design philosophy will become "single-crystal silicon of the quantum era"—a designable, scalable, engineerable quantum hardware substrate.