Direct observation of Cu in high-silica chabazite zeolite by electron ptychography using Wigner distribution deconvolution
Kazutaka Mitsuishi, Katsuaki Nakazawa, Ryusuke Sagawa, Masahiko Shimizu, Hajime Matsumoto, Hisashi Shima, Takahiko Takewaki
Abstract
Direct observation of Cu in Cu-chabazite (CHA) zeolite has been achieved by electron ptychography using the Wigner distribution deconvolution. The imaging properties of ptychographically reconstructed images were evaluated by comparing the intensities of six-membered-ring columns of the zeolite with and without Cu using simulated ptychography images. It was concluded that although false contrast may appear at Cu-free columns for some acquisition conditions, ptychography can discriminate columns with and without Cu. Experimental observation of CHA with and without Cu was performed. Images obtained from the Cu-containing sample showed contrast at the six-membered-rings, while no contrast was observed for the Cu-free sample. The results show that ptychography is a promising technique for visualizing the atomic structures of beam-sensitive materials.