Electric Field Sensing Using an NV Center Under Perpendicular Magnetic Field

Nitrogen-vacancy (NV) centers in diamond can sense locally both magnetic and electric fields and hence may offer unique insight into strongly correlated matter. While NV magnetic sensing is well established, NV electric sensing is not yet widely utilized. Here we explored electric field sensing using an NV in the presence of a strong magnetic field acting perpendicular to the NV axis. We use shallow NVs (~20nm below the surface) in bulk diamonds and nanotips to explore the optimal conditions for electric field sensing. Under a perpendicular field, the original spin states mix into bright and dark states. These sates hybridize with the ¹⁵N nuclear spin due to hyperfine interaction, giving rise to periodic modulations in the spin-echo signal. Surprisingly, this hyperfine coupling strength appears to be tunable by the magnitude of the perpendicular field and is linear at least up to 200G. These findings may offer a new pathway for prolonging the coherence of the nuclear spin.