Quantum Faraday and Kerr rotations in graphene
Quantum Faraday and Kerr rotations in graphene
复制标题
DOI：
10.1038/ncomms2866
复制
发表时间：
2013-05
影响因子：
16.6
通讯作者：
Ryo Shimano;Go Yumoto;J. Y. Yoo;Ryusuke Matsunaga;Shin-ichi Tanabe;Hiroki Hibino;Takahiro Morimoto;Hideo Aoki
中科院分区：
文献类型：
--
作者：
Ryo Shimano;Go Yumoto;J. Y. Yoo;Ryusuke Matsunaga;Shin-ichi Tanabe;Hiroki Hibino;Takahiro Morimoto;Hideo Aoki
石墨烯是一种单层碳原子片，由于其电子的无质量狄拉克色散而表现出有趣的电子特性。一个引人注目的例子是半整数量子霍尔效应，它支持狄拉克锥的存在，或者等价地，非零（π）贝里（拓扑）相的存在。令人好奇的是，狄拉克电子的这些反常特征将如何影响光学性质。在这里，我们观察了石墨烯在太赫兹频率范围内的量子磁光法拉第和克尔效应。我们的研究结果精确地探测到了法拉第和克尔旋转中的量子平台，这是狄拉克电子的标志，旋转角度由精细结构常数定义。除了在概念上有趣之外，光学体系中强大的量子霍尔高原可能为新的基于石墨烯的光电应用开辟道路。
Graphene, a monolayer sheet of carbon atoms, exhibits intriguing electronic properties that arise from its massless Dirac dispersion of electrons. A striking example is the half-integer quantum Hall effect, which endorses the presence of Dirac cones or, equivalently, a non-zero (π) Berry’s (topological) phase. It is curious how these anomalous features of Dirac electrons would affect optical properties. Here we observe the quantum magneto-optical Faraday and Kerr effects in graphene in the terahertz frequency range. Our results detect the quantum plateaus in the Faraday and Kerr rotations at precisely the quantum Hall steps that hallmark the Dirac electrons, with the rotation angle defined by the fine-structure constant. The robust quantum Hall plateaus in the optical regime, besides being conceptually interesting, may open avenues for new graphene-based optoelectronic applications.