Theory of Atomic-Resolution Differential Phase Contrast STEM

Takehito Seki, Gabriel Sánchez-Santolino, Ryo Ishikawa, Yuichi Ikuhara and Naoya Shibata

Abstract: Differential phase contrast scanning transmission electron microscopy (DPC STEM) now gathers considerable attention because this technique allows us to directly visualize electromagnetic fields inside materials and devices. In recent years, DPC STEM has been applied to atomic-resolution STEM, and electric field inside atoms, that is atomic electric field, has been shown to be observable in real space. In the present report, we would like to summarize theoretical understanding of atomic-resolution DPC image formation mechanisms and how to quantify such local fields by using segmented and pixelated detectors by investigating phase contrast transfer functions.

Key words: Differential phase contrast, STEM, Atomic electric field, Segmented detector