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【学术报告】王中长:二氧化钛晶界的原子与电子结构重构

作者:liuzhaotun(转唐梅) 浏览次数: 发布日期:2017-10-16 16:36:41

报 告 人: 王中长

联系方式:International Iberian Nanotechnology Laboratory

电子邮箱zhongchang.wang@inl.int

报告人简介:王中长, 伊比利亚国际纳米科技实验室高级研究员,PI。2007获日本东京大学博士学位。2008年至2009年,任日本东北大学助手,2009年至2012年,任日本东北大学助理教授,2013年至2017年,任日本东北大学副教授。2016年,伦敦大学学院访问学者。2017年起,任伊比利亚国际纳米科技实验室高级研究员、PI。一直从事无机材料的原子层面制备、表征、性能及第一性原理和分子动力学计算。在材料、相界面的基本原子结构与物理性能直接关联方面取得了较大进展。负责了19项包括日本国文部省科学研究费在内的国家和企业课题研究。在国际著名学术期刊Nature, Nature Nanotech., Nature Commun., Nano Lett., Adv. Mater., Angew Chemie, ACS Nano., Phys. Rev.等上发表SCI检索论文190余篇。其中Nature以及子刊10篇。参与两部英文专著的撰写。在35个主要的国际会议上做邀请或者专题报告。相关研究成果获国际材料晶界与相大会年轻科学家奖,日本材料学会材料研究促进奖,国际材料联合会年轻科学家奖, NEC最高科学技术奖等。相关成果被朝日新闻、读壳新闻、日本经济新闻、东京新闻等宣传。

报告题目: 二氧化钛晶界的原子与电子结构重构  (Atomic and Electronic Reconstruction of Grain Boundaries in Titanium Dioxide)

报告时间:10月17日(周二)上午10点

报告地点:21教学楼105

内容摘要:Polycrystalline TiO2 finds numerous technological applications where its grain boundaries (GBs) are known to influence its functionality. Light sensitive photovoltaics, oxygen transfer catalysts and host for semiconductor spintronics are just a few important examples. Grain boundaries in these systems can be either beneficial or detrimental to applications and have been a subject of intensive researches. Here, we fabricate the pristine (112)[10] symmetric tilt model GBs of TiO2 using the bicrystal technique. We combine advanced electron microscopy, spectroscopy, and first-principles calculations to probe individual TiO2 GB subject to treatment at different atmosphere, and demonstrate that stimulated structural defects can self-assemble at GB, forming an ordered superstructure, which results in GB nonstoichiometry and reconstruction at the atomic scale. Such structural transformation is accompanied with electronic transition at GB. In addition, we also fabricate the other pristine (221)[10] symmetric tilt model GB of TiO2, and offer direct evidence that there occurs a periodic GB superstructure with a couple of Ti and Ti-O columns exactly on the mirror plane. We also identify coupled bright columns, which show a broader image contrast than its Ti-O mixed counterparts in the bulk. Such an interesting aggregation of oxygen atoms at GB shall give rise to electronic structure shift of the Σ13 GB by showing an electronic transformation at GB from rutile-like to anatase-like structure.