报告题目：Spin- and pseudospin-symmetry breaking induced Half-metallic Dirac cone in graphene

　　主讲嘉宾：陈明星博士 美国威斯康星大学密尔沃基分校

　　时间：12月28日（星期一）下午15：30

　　地点：工艺楼406会议室

　　内容摘要：The discovery of graphene has inspired intense interest in graphene-based nanostructures. One fascinating feature of graphene is the combination of real spin and pseudospin which gives rise to rich physics in this unique two dimension system, e.g. unusual quantum Hall ect. The breaking of these symmetries could lead to interesting physical phenomena4{7 , such as gap opening due to pseudospin symmetry breaking in supported graphene, additional Hall plateau induced by SU(4) spin-pseudospin symmetry breaking due to electron-electron interaction, and valley polarization caused by inversion symmetry breaking.  The edge states of ZGNRs also carry unique spin and pseudospin information: spins are ferromagnetically coupled within each edge but antiferromagnetically coupled between edges, that is, within each edge the spin polarized state is spatially located on only one sublattice (pseudospin). In this talk, I will demonstrate that the unique combination of spin and pseudospin in ZGNRs can also be used to manipulate properties of graphene. A half-metallic state is surprisingly observed in AB (Bernal) stacking ZGNRs/graphene as a result of spin- and pseudospin-symmetry breaking caused by the special stacking. Remarkably, half-metallic Dirac cones are formed at K (K') near the Fermi level, which have profound implications for both fundamental investigations and practical applications.

　　报告人简介：陈明星博士于2012年3月从维也纳大学物理系获得博士学位。2012年-至今在美国威斯康星大学密尔沃基分校从事博士后研究。长期从事固体材料电子结构、电子输运性质的第一性原理计算以及相关方法发展的研究。在固体材料热电输运、表面与界面纳米结构如石墨烯、纳米石墨带以及硅烯等方面发表论文15 篇，其中包括Nature Communications、Nano Letter 等刊物。