Graphene nanoribbons in criss-crossed electric and magnetic fields
Graphene nanoribbons in criss-crossed electric and magnetic fields
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DOI：
10.1098/rsta.2010.0215
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发表时间：
2010-12
期刊：
影响因子：
--
通讯作者：
O. Roslyak;G. Gumbs;Danhong Huang
中科院分区：
文献类型：
--
作者：
O. Roslyak;G. Gumbs;Danhong Huang
在相互垂直的电场和磁场中，石墨烯纳米带(GNR)的能带结构和电子输运性质发生了显著的变化。横跨带子的强电场诱导了多个手性狄拉克点，填补了扶手椅GNR中的半导体间隙。垂直磁场诱导部分形成的朗道能级和色散表面束缚态。每个外加磁场本身都保持了子带色散的偶数对称性Ek=E−k。当它们一起应用时，它们将色散宇称反转为奇数，这使得Ee，k=−Eh，−k，并在对应于带状势能变化的能量范围内混合电子和空穴子带。这导致了弹道电导在这个能量范围内的振荡。破碎的时间反转对称性在圆偏振光的吸收中提供了二色性。结果，人们可以观察到电增强的法拉第旋转，因为带的边缘提供了相当大的态密度的形成。
Graphene nanoribbons (GNRs) in mutually perpendicular electric and magnetic fields are shown to exhibit dramatic changes in their band structure and electron-transport properties. A strong electric field across the ribbon induces multiple chiral Dirac points, closing the semiconducting gap in armchair GNRs. A perpendicular magnetic field induces partially formed Landau levels as well as dispersive surface-bound states. Each of the applied fields on its own preserves the even symmetry Ek=E−k of the sub-band dispersion. When applied together, they reverse the dispersion parity to be odd, which gives Ee,k=−Eh,−k, and mix the electron and hole sub-bands within the energy range corresponding to the change in potential across the ribbon. This leads to oscillations of the ballistic conductance within this energy range. The broken time-reversal symmetry provides dichroism in the absorption of the circularly polarized light. As a consequence, one can observe electrically enhanced Faraday rotation, since the edges of the ribbon provide formation of the substantial density of states.