Roadmap: 2D Materials for Quantum Technologies

Two-dimensional (2D) materials have emerged as a versatile and powerful platform for quantum technologies, offering atomic-scale control, strong quantum confinement, and seamless integration into heterogeneous device architectures. Their reduced dimensionality enables unique quantum phenomena, including optically addressable spin defects, tunable single-photon emitters, low-dimensional magnetism, gate-controlled superconductivity, and correlated states in Moiré superlattices. This Roadmap provides a comprehensive overview of recent progress and future directions in exploiting 2D materials for quantum sensing, computation, communication, and simulation. We survey advances spanning spin defects and quantum sensing, quantum emitters and nonlinear photonics, computational theory and data-driven discovery of quantum defects, spintronic and magnonic devices, cavity-engineered quantum materials, superconducting and hybrid quantum circuits, quantum dots, Moiré quantum simulators, and quantum communication platforms. Across these themes, we identify common challenges in defect control, coherence preservation, interfacial engineering, and scalable integration, alongside emerging opportunities driven by machine$-$learning$-$assisted design and integrated experiment$-$theory feedback loops. By connecting microscopic quantum states to mesoscopic excitations and macroscopic device architectures, this Roadmap outlines a materials-centric framework for integrating coherent quantum functionalities and positions 2D materials as foundational building blocks for next-generation quantum technologies.

💡 Research Summary

This roadmap provides a comprehensive survey of how two‑dimensional (2D) materials are reshaping the landscape of quantum technologies, covering quantum sensing, emitters, computation, spintronics, magnonics, nonlinear photonics, cavity engineering, superconducting circuits, quantum dots, moiré quantum simulators, and quantum communication. The authors begin by emphasizing the unique advantages of atomically thin crystals: extreme tunability of electronic structure, strong quantum confinement, and the ability to stack disparate layers with precise twist angles, creating moiré superlattices that host flat bands and correlated phases.

In the sensing section, spin defects in wide‑band‑gap 2D insulators such as hexagonal boron nitride (hBN) are highlighted as surface‑proximate analogues of diamond NV centers. Their planar geometry places the active spin within a few angstroms of the target, dramatically boosting magnetic, electric, and thermal field sensitivity. The paper reviews deterministic defect creation (ion implantation, electron irradiation, laser processing), charge state control, isotopic purification, and dynamical decoupling schemes that extend coherence times toward the microsecond regime.

The quantum‑emitter chapter details strain‑localized excitons in transition‑metal dichalcogenides (TMDs) and hBN, which act as tunable single‑photon sources. Because the emission energy can be modulated by local strain, electrostatic gating, or dielectric environment, arrays of near‑identical emitters can be fabricated. Valley‑selective selection rules and broken inversion symmetry enable efficient second‑harmonic generation and polarization‑controlled photon emission. Coupling these emitters to photonic cavities or plasmonic resonators yields strong exciton‑photon coupling, paving the way for polaritonic devices, vacuum‑field chemistry, and light‑driven superconductivity.

A major focus is the data‑driven discovery of quantum defects. High‑throughput density‑functional theory (DFT) combined with GW‑Bethe‑Salpeter calculations predicts formation energies, optical transition levels, and spin properties for thousands of candidate defects. Machine‑learning pipelines (graph neural networks, Bayesian optimization) accelerate screening, while closed‑loop experimental validation refines the models. This integrated computational‑experimental workflow is presented as essential for rapidly identifying viable quantum‑defect platforms.

Spintronic and magnonic applications are surveyed next. Graphene spin valves demonstrate long spin diffusion lengths and efficient injection, while 2D magnetic semiconductors (e.g., CrI₃, Fe₃GeTe₂) exhibit gate‑tunable anisotropy and damping, enabling reconfigurable magnonic waveguides and spin‑wave logic. The authors discuss how low‑dimensionality reduces magnon losses and facilitates coupling to microwave photons, opening hybrid spin‑photon architectures.

Superconducting quantum circuits based on atomically thin superconductors (NbSe₂, TaS₂) are described. Gate‑controlled critical currents and transition temperatures allow the fabrication of Josephson junctions and qubits directly from 2D layers. Hexagonal boron nitride serves as a low‑loss dielectric for transmon and fluxonium devices, while the atomically flat interfaces improve coherence by minimizing dielectric loss and two‑level system noise.

The roadmap also covers quantum dots and single‑photon detectors built from graphene and TMD quantum dots, emphasizing electrical tunability, high carrier mobility, and compatibility with on‑chip photonic integration.

Moiré superlattices formed by twisted bilayers or lattice‑mismatched heterostructures are highlighted as a versatile platform for quantum simulation. Flat bands enhance electron‑electron interactions, giving rise to Mott insulating states, unconventional superconductivity, and Chern insulating phases that can be tuned by electrostatic gating, pressure, or optical pumping. These systems provide programmable Hamiltonians for analog quantum simulators, bridging material design and many‑body physics.

In quantum communication, deterministic single‑photon emitters in hBN and strain‑engineered TMDs are shown to achieve competitive key rates and low quantum bit error ratios in quantum‑key‑distribution (QKD) experiments. Integration with nanophotonic waveguides and fiber networks demonstrates the feasibility of scalable, chip‑based quantum communication architectures.

Across all topics, the authors identify four recurring challenges: (1) atomic‑scale defect control and reproducibility, (2) preservation of spin and optical coherence against nuclear‑spin noise and charge fluctuations, (3) engineering low‑loss, atomically sharp interfaces for heterogeneous integration, and (4) developing scalable fabrication processes compatible with existing quantum‑hardware platforms. They argue that overcoming these hurdles requires a synergistic approach that combines advanced synthesis, high‑resolution microscopy/spectroscopy, quantum‑aware electronic‑structure theory, and machine‑learning‑assisted materials design within a closed‑loop feedback system.

The conclusion positions 2D materials as foundational building blocks for the next generation of quantum technologies, capable of delivering integrated sensing, computation, communication, and simulation functionalities on a single, atomically thin platform. The roadmap is intended as a reference for researchers, funding agencies, and policy makers to guide future investments and collaborative efforts in this rapidly evolving field.