Study of strontium titanate (SrTiO₃) with ambient pressure XPS
报告人
Prof. Bongjin Simon Mun
Gwangju Institute of Science and Technology, Gwangju, Korea
报告时间
2022年6月8日 16:00-18:00
主办方
国家同步辐射实验室
直播二维码
直播海报
报告人介绍
Prof. Bongjin Simon Mun got the Ph.D in Physics from University of California, Davis (Advisor: Prof. Charles Fadley) in 2001. Then, Mun worked at Intel Corp. as a Senior Process Engineer before joining Advanced Light Source, Lawrence Berkeley National Laboratory as a beamline scientist in 2002. In 2007, Mun joined the Hanyang University in Korea to pursue academic career, then moved to Gwangju Institute of Science and Technology as a faculty member in the department of Physics and Photon Science. Prof. Bongjin Simon Mun has been the director of Center for Advanced X-ray Science (SRC), Gwangju Institute of Science and Technology since 2020. His main research interest is to investigate the correlation between surface chemical properties and electronic structures under reaction conditions. At present, he has published 200+ papers in Science, Nat. Common., Sci. Advance., JACS, ACS Catal., Adv. Energy Mater. and other magazines. He has been cited more than 18000 times and the H-indexs is 45.
报告摘要
Strontium titanate (SrTiO3), having ABO3 perovskite structure, is well known for interesting physical properties, excellent chemical/thermal stability and good lattice matching with other perovskites. Moreover, SrTiO3 has been extensively used as a substrate material for the fabrication of various heterogeneous structures, including ferroelectric SrRuO3, Mott insulator LaTiO3, and superconductor YBa2Cu3O7-δ, making the study of interface at the heterogeneous structures important. The reporter utilizes AP-XPS to investigate the chemical properties of SrTiO3 surface under similar conditions to the fabrication of ferroelectric SrRuO3 heterogeneous structures, e.g. elevated oxygen pressure and temperature. In order to monitor the chemical redox state and ionic/electronic charge transfer behavior underneath the surface, depth resolved AP-XPS is utilized. During thermal annealing process under 0.1 mbar oxygen pressure, Sr elements are being pulled over to the outermost layer and the well-ordered SrO1+x is formed on top surface. The nature of core-level shift and oxide formation, i.e. the formation of charge depletion layer, will be discussed.