  The ability to sensitively image electric fields is important for
understanding many nanoelectronic phenomena, including charge accumulation at
surfaces and interfaces and field distributions in active electronic devices. A
particularly exciting application is the visualization of domain patterns in
ferroelectric and nanoferroic materials owing to their potential in computing
and data storage. Here, we use a scanning nitrogen-vacancy (NV) microscope,
well known for its use in magnetometry, to image domain patterns in
piezoelectric (Pb[Zr$_{x}$Ti$_{1-x}$]O$_{3}$) and improper ferroelectric
(YMnO$_{3}$) materials through their electric fields. Electric field detection
is enabled by measuring the Stark shift of the NV spin using a gradiometric
detection scheme. Analysis of the electric field maps allows us to discriminate
between different types of surface charge distributions, as well as to
reconstruct maps of the three-dimensional electric field vector and charge
density. The ability to measure both stray electric and magnetic fields under
ambient conditions opens exciting opportunities for the study of multiferroic
and multifunctional materials and devices.
