| Abstract Scope |
The charge density distribution in materials dictates their structure and properties. While measuring charge density of bulk materials is possible using X-ray or electron diffraction techniques, resolving charge density in inhomogeneous structures remains a great challenge. In this talk, I will present a real space imaging technique to map the local charge density between atoms using a confined electron probe of 0.6 Å in size in scanning transmission electron microscope, along with an angle resolved pixelated fast electron detector. As an example, using this technique, we directly imaged the interfacial charge distribution and ferroelectric polarization configuration at the ferroelectric/insulator heterojunction with the sub-Å resolution, and discovered electronic charge accumulated at the interface induced by the penetration of polarization field inside the insulator. The charge density imaging established in this work advances electron microscopy from detecting atoms to imaging electrons, paving a new route to study local bonding in crystalline solids. |