Expérimental
Quantum sensors take advantage of the extreme sensitivity of quantum systems to external perturbations to accurately measure a broad range of physical quantities such as acceleration, rotation, magnetic and electric fields, or temperature. Among a wide variety of quantum systems employed for sensing purposes, the nitrogen-vacancy (NV) defect in diamond has garnered considerable attention in the last decade for the development of a new generation of magnetometers providing an unprecedented combination of spatial resolution and magnetic sensitivity under ambient conditions. The goal of the present project is to extend the functionalities of NV-based quantum microscopes towards the detection of electric fields at the nanoscale, in order to study ferroelectric textures. After a careful characterization of the performances of the NV-based electrometer, we will apply NV-based electrometry to the non-perturbative nanoscale imaging of domain walls in standard ferroelectric materials, before investigating more complex materials like the multiferroic bismuth ferrite or twisted bilayers of van der Waals materials like h-BN.