Nanoscale Electric Field Imaging with an Ambient Diamond-NV Scanning Probe

The ability of mapping local electric fields is crucial for understanding material's underlying physics. Most current techniques are based on measuring potentials, where cryogenic conditions are usually required to achieve high sensitivity. These include single-electron transistors (SET), scanning tunneling microscopy (STM), Kelvin probe, and scanning capacitance microscopy. Here we demonstrate imaging local electric fields with a scanning nitrogen-vacancy (NV) tip, in the presence of a bias magnetic field perpendicular to the NV axis. The long NV coherence time and atomic size enable high sensitivities and nanoscale resolution (tens of nm) under ambient conditions. This scanning NV electrometry, together with its established magnetic sensing capabilities, provides a new and superior tool for measuring condensed matter phenomena.