ADVANCED ELECTRON
MICROSCOPY & FUNCTIONAL
IMAGING LABORATORY

Our research focuses on the application of aberration-corrected
STEM with emphasis on the unprecedented atomic scale imaging
techniques aimed at unraveling and understanding the various material
property-dependent device performance.

For several decades, studying the microstructure of materials was quite challenging as most of the research works were theoretical. More importantly, providing direct evidence of atomic scale evolution of material properties was nearly impossible due to the limited analytical tools and techniques. However, with the invention of new analysis and interpretational techniques, elucidating the correlation between material nanostructure and device characteristics has become increasingly important for the development of novel materials. Our research focuses on applying aberration-corrected STEM techniques, emphasizing the unprecedented atomic scale imaging techniques to unravel and understand the material property-dependent device performance at the atomic scale. In-depth investigations of phenomena such as atomic scale visualization of antisite defects (such as those observed in LiFePO4) are tackled.

RESEARCH INTEREST

PUBLICATIONS

  • Daseob Yoon, Gi-Yeop Kim, Sanbae Yu, Yujeong Lee, Si-Young Choi and Junwoo Son*, "Threading dislocation annihilation by oxygen vacancies in BaSnO3 epitaxial films with high electron mobility", Journal of Alloys and Compounds 1032, 181059 [DOI] https://doi.org/10.1016/j.jallcom.2025.181059

  • Jinhyuk Jang†, Yeongrok Jin†, Yeon-Seo Nam†, Heung-Sik Park, Jaegyu Kim, Kyeong Tae Kang, Yerin So, Jiwoung Choi, Youngchang Choi, Jaechan Shim, Panithan Sriboriboon, Dong Kyu Lee, Kyoung-June Go, Gi-Yeop Kim, Seungbum Hong, Jun Hee Lee, Daesu Lee, Myung-Geun Han, Junwoo Son, Yunseok Kim, Hiroki Taniguchi, Seokhyeong Kang, Jang-Sik Lee, He Tian, Chan-Ho Yang, Yimei Zhu, Sang-Wook Cheong, Woo Seok Choi*, Jaekwang Lee*, and Si-Young Choi* († equally contributed authors), "Sub-unit-cell-segmented ferroelectricity in brownmillerite oxides by phonon decoupling", Nature Materials XX, 1-8 (2025) [DOI] https://doi.org/10.1038/s41563-025-02233-7

  • Min Young Kim, Dongkyu Lee, June Ho Lee, Donghwa Lee, Gi-Yeop Kim, Si-Young Choi, Joseph P. Heremans, and Hyungyu Jin*, "Oxygen Vacancy Defect Engineering for TransverseThermoelectric Enhancement: a Novel Extrinsic Pathwaybeyond Intrinsic Approaches", Advanced Science XX, 2502892 (2025) [DOI] http://doi.org/10.1002/advs.202502892

  • Dong-Hwan Yang†, Minjeong Kim†, Jinyoung Ko, Gi-Yeop Kim, Hyung Gyu Park, Sarah S. Park, Kyung Ho Cho, Ji Sun Lee, Jong-San Chang, U-Hwang Lee, Ryo Ishikawa, Naoya Shibata, Yousung Jung, Jonghwan Kim*, Teruyasu Mizoguchi*, and Si-Young Choi* († equally contributed authors), “Direct Imaging of Co-CUK-1 Framework with H2O Guests”, Small XX, XX (Accepted)

  • Joonhee Ma†, Wooseok Lee†, Jae Hak Kim, Jaemin Jeong, Kyu-min Jo, Si-Young Choi*, Seoin Back*, and Soo Young Kim* († equally contributed authors), "Leveraging the Intermetal Distance in Dual-Atom Catalysts: Revealing Optimized Synergistic Interactions for CO2 Electroreduction", ACS Nano 19, 17953-18888 (2025) [DOI] https://doi.org/10.1021/acsnano.5c03160