Landau-level splitting in graphene in high magnetic fields
Landau-level splitting in graphene in high magnetic fields
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DOI：
10.1103/physrevlett.96.136806
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发表时间：
2006-04-07
影响因子：
8.6
通讯作者：
Kim, P
中科院分区：
文献类型：
--
作者：
Zhang, Y;Jiang, Z;Kim, P
在45 T的强磁场下，研究了高质量石墨烯样品中二维电子和空穴的量子霍尔（QH）效应。在填充因子nu=0、+/- 1和+/- 4处，在磁场B bbb20 T处发现了QH平台，表明先前观察到的QH态在nu=+/- 4（平行于n平行于+1/2）处的四倍简并度提升，其中n为朗道能级指数。特别是nu=0，+/- 1 QH平台的存在表明电荷中性Dirac点的朗道能级分裂为四个亚能级，提升了亚晶格和自旋简并。在倾斜磁场中研究了nu=+/- 4处的QH效应，该效应可归因于n=1朗道能级的自旋简并的提升。
The quantum Hall (QH) effect in two-dimensional electrons and holes in high quality graphene samples is studied in strong magnetic fields up to 45 T. QH plateaus at filling factors nu=0,+/- 1,+/- 4 are discovered at magnetic fields B > 20 T, indicating the lifting of the fourfold degeneracy of the previously observed QH states at nu=+/- 4(parallel to n parallel to+1/2), where n is the Landau-level index. In particular, the presence of the nu=0,+/- 1 QH plateaus indicates that the Landau level at the charge neutral Dirac point splits into four sublevels, lifting sublattice and spin degeneracy. The QH effect at nu=+/- 4 is investigated in a tilted magnetic field and can be attributed to lifting of the spin degeneracy of the n=1 Landau level.