Electron Holography as a Tool for Nano-Scale Measurements of Bonding and Charg

Date: 
Tue, 07/01/202011:00
Location: 
Seminar Hall, Los Angeles Building, entrance floor

Prof. AmiAmit Kohnt Kohn (TAU)

Department of Materials Science and Engineering, Tel Aviv University


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Off-axis electron holography (OAEH) is a method applied in transmission electron microscopy (TEM) in order to reconstruct the phase of an electron wave after it has traversed through a thin sample. When applied at nanometer scale spatial resolution, the reconstructed phase enables to extract both electrostatic and magnetic fields.

 

For this talk, I will focus on the measurement of electrostatic potentials as a tool to characterize bonding and charge redistribution in crystals. I will describe the experiment and data analysis followed by examples from current research on measuring the mean-inner-potential in sapphire and graphite, and charged-defect distributions in nanoscale MgO×Al2O3 spinel. The latter example also demonstrates the ability in the TEM to complement OAEH measurements with additional characterization of the same crystals, in this case electron energy-loss spectroscopy for detecting the distribution of anti-site charged point defects.