Nanoscale quantum sensing of quantum materials through a single spin magnetometer

Advanced sensing and imaging techniques are integral to scientific research, technological progress and hence to a wide range of applications in medical therapy as well as environmental science. Known as single spin quantum bits, nitrogen vacancy (NV) centers, optically active atomic defects in diamond are naturally relevant in this context due to their excellent quantum coherence, single-spin addressability, and remarkable versatility over a broad temperature range. Exploiting this cutting-edge quantum sensing platform, we demonstrate non-invasive measurement of spin transport and dynamic properties of magnetic insulators. The observed strong coupling between NV centers and spin waves offers new opportunities for designing next-generation, solid-state-based quantum operation platforms. Finally, we further illustrate the capability of NV centers in probing the local thermal environment of insulator-to-metal transition (IMT) in strongly correlated Mott insulators, providing the first direct evidence for non-thermally driven IMT. Our results demonstrate the unique capability enabled by NV centers in exploring the exotic local spin and charge behaviors in quantum material systems.