아래와 같이 세미나를 개최하오니 많이 참석해 주시기 바랍니다. 아 래 제목: Atomic-scale polar oxide heterostructures: Growth and interfacial properties 연사: Dr. Ho Nyung Lee (Oak Ridge National Laboratory) 일시: 2009년 7월 17일(금) 오후 4:30 - 5:30 장소: 물리학과 세미나실(31355호실) 문의: 강원남 교수 (290-5904) 초록: The discovery of high mobility, two-dimensional electron gases formed at the interface of two insulating oxides opened a door to a fascinating new approach for realizing oxide electronics. However, the origin of the two-dimensional conductivity found in, e.g. LaAlO3/SrTiO3 is still unclear and the underlying mechanism that supports the idea is still under debate as a similar conductivity can be readily achieved by doping SrTiO3 substrates with oxygen vacancies under reduced conditions. In this seminar, I will present a summarized work on the current status of understanding the underlying mechanism and propose another growth related issue, which support the properties and behaviors observed previously from samples synthesized by pulsed laser deposition. Moreover, interfacial transport properties found in other type of oxides will be presented as a comparison, emphasizing the importance of atomic-scale stacking of oxide materials that can open a door to developing a completely new class of functional materials and to discovering novel properties and/or unobserved behaviors. In addition, as a second topic, based on Z-contrast and phase contrast imaging at the atomic scale, we found that the way to compensate depolarization field in ferroelectric materials is drastically depend on the type of material’s electronic ground states. Thus, I will discuss about the polar stability of ferroelectricity at interfaces in ferroelectric-dielectric and ferroelectric-metal heterostructures, probed by TEM with sub-angstrom resolution.