报告人：王中长（日本东北大学副教授）
报告题目：Defects and their Segregation in Grain Boundaries of Oxides
报告时间：2014年4月9号，星期三， 9:30 AM -11:30 AM
报告地点：芝纶馆308会议室
摘要：
Local atomic structure, chemistry and bonding at interfaces or grain boundaries can often radically alter properties of materials. However, to catch such an impact on an atomistic level remains extremely challenging. Although the direct imaging using scanning transmission electron microscopy (STEM), the highest resolution so far, makes the atomic-scale characterization reality, it is still not always straightforward to interpret the observed images especially in the case of interfaces, for which their own complications might cause incomplete imaging.
In this talk, we combine advanced STEM imaging with first-principles calculations to address the structures of a few technologically important interfacial systems and relate them to property on atomic level. We select a couple of important functional oxides, Al2O3, MgO and ZnO, to demonstrate that atomic-scale detection and analysis of every individual defects in the defective grain boundaries in complex materials are now becoming possible. We can provide definitive evidence of selected segregation of impurities and defects to different grain boundaries that could affect significantly properties of materials. The combined technique to resolve and identify defects in the buried interfaces with unknown composition and structure should be applicable to other types of fundamental extended defect and a wide range of materials, including metals.
Local atomic structure, chemistry and bonding at interfaces or grain boundaries can often radically alter properties of materials. However, to catch such an impact on an atomistic level remains extremely challenging. Although the direct imaging using scanning transmission electron microscopy (STEM), the highest resolution so far, makes the atomic-scale characterization reality, it is still not always straightforward to interpret the observed images especially in the case of interfaces, for which their own complications might cause incomplete imaging.
In this talk, we combine advanced STEM imaging with first-principles calculations to address the structures of a few technologically important interfacial systems and relate them to property on atomic level. We select a couple of important functional oxides, Al2O3, MgO and ZnO, to demonstrate that atomic-scale detection and analysis of every individual defects in the defective grain boundaries in complex materials are now becoming possible. We can provide definitive evidence of selected segregation of impurities and defects to different grain boundaries that could affect significantly properties of materials. The combined technique to resolve and identify defects in the buried interfaces with unknown composition and structure should be applicable to other types of fundamental extended defect and a wide range of materials, including metals.
报告人简介：
Dr. Wang is currently an associate professor in World Premier International Research Center, Advanced Institute for Materials Research, Tohoku University. He received his PhD in Materials Engineering from The University of Tokyo in 2007. He focuses on the atomic-scale preparation, characterization, and property measurement of metallic and advanced materials and on the first-principles calculations and molecular dynamics calculations. He made contribution in the fields of atomic structures of materials, phases and interfaces and their correlation with physical and mechanical properties. He received a total of thirteen foundations from the Japanese government and companies. He has authored and co-authored 101 peer-reviewed papers in Nature, Nat. Nanotech., Nat. Commun. Adv. Mater., Angew Chemie, Phys. Rev. and Appl. Phys. Lett., in which a total of 33 papers have an impact factor of more than 3. He has given 25 invited talks and obtained several awards from Japan and US. The major achievements have been appeared in many major Japanese newspapers.
Dr. Wang is currently an associate professor in World Premier International Research Center, Advanced Institute for Materials Research, Tohoku University. He received his PhD in Materials Engineering from The University of Tokyo in 2007. He focuses on the atomic-scale preparation, characterization, and property measurement of metallic and advanced materials and on the first-principles calculations and molecular dynamics calculations. He made contribution in the fields of atomic structures of materials, phases and interfaces and their correlation with physical and mechanical properties. He received a total of thirteen foundations from the Japanese government and companies. He has authored and co-authored 101 peer-reviewed papers in Nature, Nat. Nanotech., Nat. Commun. Adv. Mater., Angew Chemie, Phys. Rev. and Appl. Phys. Lett., in which a total of 33 papers have an impact factor of more than 3. He has given 25 invited talks and obtained several awards from Japan and US. The major achievements have been appeared in many major Japanese newspapers.