Schematic of the NV and the measurement scheme. a, Schematic drawing of the NV centre with one nitrogen at a carbon lattice site and an adjacent vacancy. b, Simulated absolute electric field 6 μm below the microstructure (depth of the NV) for an applied voltage difference of 1 V
The ability to sensitively detect individual charges under ambient conditions would benefit a wide range of applications across disciplines. However, most current techniques are limited to low-temperature methods such as single-electron transistors single-electron electrostatic force microscopy and scanning tunneling microscopy. Here we introduce a quantum-metrology technique demonstrating precision three-dimensional electric-field measurement using a single nitrogen-vacancy defect centre spin in diamond. An a.c. electric-field sensitivity reaching 202±6 V cm−1 Hz−1/2 has been achieved. This corresponds to the electric field produced by a single elementary charge located at a distance of ~150 nm from our spin sensor with averaging for one second. The analysis of the electronic structure of the defect centre reveals how an applied magnetic field influences the electric-field-sensing properties. We also demonstrate that diamond-defect-centre spins can be switched between electric- and magnetic-field sensing modes and identify suitable parameter ranges for both detector schemes. By combining magnetic- and electric-field sensitivity, nanoscale detection and ambient operation, our study should open up new frontiers in imaging and sensing applications ranging from materials science to bioimaging.
Electronic charge distributions responsible for the x (left) and y (right) components of the electric dipole momentsof the ground and excited triplet states.The solid spheres represent the nuclei of the respective atoms neighbouring the vacancy (transparent). The positive and negative contributions to the charge distributions are red and blue respectively. The coordinate axes are defined such that the z axis coincides with the axis of symmetry connecting the nitrogen and vacancy sites.