Extending the coherence of spin defects in hBN enables advanced qubit control and quantum sensing

Negatively-charged boron vacancy centers (V-B(-)) in hexagonal Boron Nitride (hBN) are attracting increasing interest since they represent optically-addressable qubits in a van der Waals material. In particular, these spin defects have shown promise as sensors for temperature, pressure, and static magnetic fields. However, their short spin coherence time limits their scope for quantum technology. Here, we apply dynamical decoupling techniques to suppress magnetic noise and extend the spin coherence time by two orders of magni-tude, approaching the fundamental T-1 relaxation limit. Based on this improvement, we demonstrate advanced spin control and a set of quantum sensing protocols to detect radiofrequency signals with sub-Hz resolution. The corresponding sensitivity is benchmarked against that of state-of-the-art NV-diamond quantum sensors. This work lays the foundation for nanoscale sensing using spin defects in an exfoliable material and opens a promising path to quantum sensors and quantum networks integrated into ultra-thin structures.

Automated summary

Researchers use dynamical decoupling techniques to suppress magnetic noise and extend the spin coherence time of optically-addressable qubits in hexagonal Boron Nitride by two orders of magnitude, approaching the fundamental T-1 relaxation limit. Advanced spin control and quantum sensing protocols are demonstrated, achieving sub-Hz resolution in detecting radiofrequency signals. This work lays the foundation for nanoscale sensing using spin defects in exfoliable materials and opens a promising path to integrated quantum sensors and quantum networks in ultra-thin structures.