Seungbum Hong

Seungbum Hong, Korea Advanced Institute of Science & Technology

Imaging Polarization and Ion Distribution in Functional Materials

Abstract
Ion is the building block of most of the ceramic materials. In ceramic materials, positive ions and negative ions are neighboring each other with mostly ionic bonding at atomic scale. Sometimes, polymer and semiconductor materials contain ions that can diffuse in and out of them. In the meantime, polarization charges of ferroelectric materials are screened by equal amount of surface charges with opposite polarity in ambient conditions. As such, imaging the location, charge as well as the velocity of each ion and polarization will greatly enhance our understanding of electrochemical properties of ferroelectric materials. Here I present our research on various imaging methods of polarization using proxies like piezoelectric strain, screening charges, and friction coefficient, which can be used to image ferroelectric polarization. Furthermore, I will show how these contrast mechanisms can be applied to energy harvesting and chemical mechanical polishing. In addition, I present our research on various imaging methods of ions and charged defects using proxies like electrochemical strain, and electric charges, which can be used to image ion distribution. Finally, I will show how imaging ion and electron conduction path can help understand the nanoscale behavior of battery materials.

Biography
Prof. Seungbum Hong graduated summa cum laude with a B.S. from the Korea Advanced Institute of Science and Technology (KAIST) in 1994 and received his Ph.D. in the field of nanoscale observation of ferroelectric thin films at KAIST in 2000. After a year of post-doc experience at EPFL in Switzerland from 2000 to 2001, he joined the probe storage project team as a project leader at Samsung Advanced Institute of Technology from 2002 to 2007. In 2007, he moved to Argonne National Laboratory as a tenured staff scientist and worked as a principal investigator in local domain and transport studies of oxide heterostructures and polymer ferroelectrics using atomic force microscopy until 2017. In 2017, Prof. Hong joined KAIST as an associate professor with tenure in the Department of Materials Science and Engineering (DMSE) and created the Materials Imaging and Integration (MII) Lab (http://mii.kaist.ac.kr). He was promoted to full professor in 2021 and served as the department head of DMSE from 2021 to 2024. He is currently the vice president in the office of academic affairs and the institution’s Global Competitiveness Advisor. He has led the Global Singularity Project of Materials and Molecular Modeling, Imaging, Informatics and Integration (M3I3) at KAIST from 2019 to 2023.

He has broad experience in linking fundamental science with industrial applications (208 peer-reviewed journal papers, 5 book editions, 8 book chapters, 79 patents) with profound knowledge in nanoscale characterization of ferroelectric and piezoelectric materials. He has been invited to major conferences or universities, has been awarded the Young Investigator Outstanding Achievement Award from the International Symposium on Integrated Ferroelectrics in 2008, was elected as the Frontier Scientist by the Korean Academy of Science and Technology in 2014, and has worked as a symposium organizer in MRS Spring 2006 and 2008, MRS Fall 2010, and APS March Meeting 2013 and as a General Chair of Asia-Pacific PFM 2019 Workshop, and PFM General Chair of Joint Conference of the IEEE International Frequency Control Symposium & IEEE International Symposium on Applications of Ferroelectrics (ISAF) in 2020 and IEEE ISAF-PFM in 2025.
He visited EPFL as an invited professor in 2014 and was appointed a senior fellow by Northwestern Argonne Institute of Science and Engineering from 2016 to 2018. He was the chair of the CNM user executive committee in 2015 and worked as a member of the MSD colloquium committee at Argonne National Laboratory and the Vision 2031 committee member at KAIST from 2017. He is currently serving the PFM International Advisory Board since 2018.