Department of Physics, University of Texas at Austin, Austin, Texas 78712-1081, USA.
Nat Mater. 2012 Apr 23;11(5):409-16. doi: 10.1038/nmat3305.
The two-dimensional electron systems in graphene and in topological insulators are described by massless Dirac equations. Although the two systems have similar Hamiltonians, they are polar opposites in terms of spin-orbit coupling strength. We briefly review the status of efforts to achieve long spin-relaxation times in graphene with its weak spin-orbit coupling, and to achieve large current-induced spin polarizations in topological-insulator surface states that have strong spin-orbit coupling. We also comment on differences between the magnetic responses and dilute-moment coupling properties of the two systems, and on the pseudospin analogue of giant magnetoresistance in bilayer graphene.
石墨烯和拓扑绝缘体中的二维电子系统由无质量狄拉克方程描述。尽管这两个系统具有相似的哈密顿量，但它们在自旋轨道耦合强度方面却是截然相反的。我们简要回顾了在具有较弱自旋轨道耦合的石墨烯中实现长自旋弛豫时间的努力现状，以及在具有较强自旋轨道耦合的拓扑绝缘体表面态中实现大电流诱导自旋极化的努力现状。我们还评论了这两个系统的磁响应和稀磁耦合性质之间的差异，以及双层石墨烯中巨磁电阻的赝自旋类似物。
