题目：Tunable Negative Magnetoresistance in graphene with in-situ hydrogenation

报告人：Jian-Hao Chen (陈建豪) 北京大学

地点： 教十二-201

时间：12月9日，周五，15:00-16:00

摘要：

The problem of unconventional magnetism in materials without d and f electrons has attracted continuous attention. In particular, a lot of efforts have been devoted to understand the origin and effects of magnetic moments induced in graphene with structure defects such as missing carbon atoms, absorption of light atoms such as hydrogen or fluorine.  We have measured the magnetoresistance (MR) of graphene at low temperature with in-situ hydrogenation in ultra-high vacuum environment.  In the low field regime, we observed a cross-over from weak localization to weak anti-localization that provides evidence for magnetic moment created by hydrogen atom absorbed on graphene and such absorption also drastically increase the spin orbit coupling of graphene.  In the high field regime, large non-saturating negative MR was found in hydrogenated graphene which could be tuned by carrier density and sample temperature. Such negative MR could also be the manifestation of local moments created by atomic hydrogen absorbed on graphene.

个人简介：

Dr. Jian-Hao Chen obtained his undergraduate degree in Zhejiang University. He obtained his PhD in Physics under the supervision of Prof. Ellen Williams at University of Maryland at College Park, Maryland, United States in 2009. Thereafter, he worked as a Research Fellow in the nanoelectronics group of Prof. Michael Fuhrer at University of Maryland and in Prof. Alex Zettl’s group at University of California at Berkeley. Since March 2013, he joined Peking University as an Associate Professor and Principle Investigator of the Laboratory for Nanoelectronics and In-Situ Quantum Transport. His present research is focused on studying the physics and applications of low-dimensional electronic materials and its nanostructures, manipulation of material properties at the atomic scale, and in-situ quantum electrical transport in ultra-high vacuum environment.  His peer-reviewed publications include three articles in Nature Physics, one article in Nature Nanotechnology and three articles in Physical Review Letters, with a total SCI citation of more than 4000.

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