Visualization of Functionalities in Oxides via Atomic Scale Imaging
|
최시영 POSTECH On the contrary to the conventional way using macroscopic measurements, neutron/X-ray diffraction, and piezoresponse force microscopy (PFM), the atomistic characterization in the field of ferroelectric materials has remained poorly understood until the last decade, when the spatial resolution have allowed the mapping of the electric field directly from the materials as well as structural distortions on an atomic scale. Visualization of the electric field by the ferroelectricity can be achieved by the recently-developed technique: the differential phase contrast (DPC)-STEM or ptychography STEM technique. In addition, we also can derive the atomic polarization from the coordinate information of all atoms. The biggest ripple effect is that the local polarization distributions in the vicinity of surfaces, interfaces, or topological defects can be understood, which are often crucial to unveil lots of ferroelectric phenomena by the nonequilibrium states. In this talk, I inform the recent trend in terms of atomistic analytical methodologies in the ferroelectric materials and further I will introduce the relevant achievements from CaTiO3 and WO3 thin films. |