Development of spin qubits in two-dimensional materials for optical quantum technologies

Optically-active defect spins in wide-bandgap materials are central components for a range of emerging quantum technologies, including quantum sensors and repeaters for quantum optical networks. Defects in diamond and silicon carbide are prime examples, where narrow optical transitions are combined with long-lived optically-accessed electronic spin coherence that can be coupled to longer-lived nuclear spin memories, all in a convenient solid-state host material. In a series of recent breakthroughs, our team has identified a new two-dimensional platform for optical quantum technologies - quantum coherent spin defects in hexagonal Boron Nitride (hBN). These spin defects show spin coherence of microseconds at room temperature and are grown into layered material <30 nm thick. This discovery opens routes to a new quantum spin-photon interface that can be incorporated to atomically thin devices and operate at ambient conditions.

A key requirement of a spin-photon interface for quantum technologies is demonstrating optical and spin coherence, and a deterministic relationship between emitted photons and the spin state. This project will build towards demonstrating spin-photon entanglement with defects in hexagonal boron nitride by establishing the fundamental photophysics of the 2D spin qubits. To realise a 2D platform for quantum technologies, the project will involve experimentally probing the optical and spin coherence of hBN defects via pulsed optically detected magnetic resonance, quantum optical measurements and optical spectroscopy and combining this work with device fabrication, theoretical modeling and materials characterisation. 

The project contributes to a wider team effort to realise quantum sensors and devices for optical quantum technologies based on defects in two-dimensional materials.

Image: Qiushi Gu