报告题目：STM Investigation of Coulomb Impurities on Graphene

报 告 人： 汪洋，加州大学伯克利分校

报告时间：12月17日(周一)下午3:30-5:30

报告地点：清华-富士康纳米纳米科技研究中心四楼会议室

报告摘要：The response of Dirac fermions to a Coulomb potential is predicted to differ significantly from how non-relativistic electrons behave in traditional atomic and impurity systems. Surprisingly, many key theoretical predictions for this ultra-relativistic regime have not been tested. Graphene, a 2D material in which electrons behave like massless Dirac fermions, provides a unique opportunity to test such predictions. Here I will talk about our scanning tunneling microscopy (STM) study of Coulomb impurities on graphene. The charged impurities on graphene display two types of behaviors: subcritical regime where Dirac fermions scatter off the charged impurities while remain their delocalized natures, and supercritical regime where a novel electronic state known as the “atomic collapse” state is formed.