郑州大学物理学院
报告摘要：
As a classic Mott insulator,VO2 has attracted worldwide attention because of its near room temperature metal-insulator transition. Using in situ transmission electron microscopy (TEM),we have systematically studied the transition mechanism of VO2 under electric field. The in situ biasing TEM experiments have shown that the stochastic conductivity in VO2 is due to the inherent stochasticity of monoclinic domain switching,which is helpful for generating random number. [1] Beside the volatile switching,we found the nonvolatile switching could also exist in VO2. With the help of the electroforming process,the Magnéli V5O9 phase will form (confirmed by TEM) and act as the conductive filament. Further experimental and theoretical results have shown that,by changing the voltage,temperature,and thickness of the film,the VO2 film could feature either volatile or nonvolatile switching. [2] Recent result has shown that VO2 could have giant nonvolatile photoinduced resistivity change under beam shining,[3] due to the injected carriers from the nearby CdS layer. This phenomenon has been studied by TEM,and electron energy loss spectroscopy results have shown that the hole doping will largely change the electronic structures and thus change the transportation behaviors of VO2,leading to an isostructural metal-insulator transition. [4]
References
[1] Shaobo Cheng,Min-Han Lee,Richard Tran,et al. Shyue Ping Ong,Ivan K. Schuller,Yimei Zhu*,PNAS,118,e2105895118 (2021)
[2] Shaobo Cheng,Min-Han Lee,Xing Li,et al.,PNAS,118,e2013676118 (2021)
[3] H. Navarro,J. d. Valle,Y. kalcheim,et al.,Appl. Phys. Lett.,118,141901 (2021)
[4] Shaobo Cheng,et al. Unpublished.
报告人简介：
程少博 ，郑州大学物理学院教授，长期从事原位透射电子显微学等相关领域的研究，近几年在Science,PNAS,Nature Communications 等期刊共发表学术论文70余篇，其中第一作者或通讯作者发表论文和专著共30余篇，包括Science Advances,PNAS（3篇）,Physical Review Letters（封面文章）,Advanced Functional Materials,Nano Letters等。2021年获得美国能源部前沿研究中心的杰出冯诺依曼博士后奖，2020年获得美国电子显微学会Postdoctoral Award,2017年获得清华大学优秀博士学位论文奖，博士论文被选编入清华大学优秀博士论文丛书并出版发行。目前担任美国物理学会（APS）期刊的青年仲裁编辑，及其他国际期刊的青年编委。
报告地点： M253
邀请人： 杨槐馨
联系人： 李俊
联系电话：82649180