Valley filter and valley valve in graphene
Valley filter and valley valve in graphene
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DOI：
10.1038/nphys547
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发表时间：
2007-03-01
期刊：
影响因子：
19.6
通讯作者：
Beenakker, C. W. J.
中科院分区：
文献类型：
--
作者：
Rycerz, A.;Tworzydlo, J.;Beenakker, C. W. J.
石墨烯用于碳电子器件的潜力取决于其不寻常的能带结构所提供的可能性，以创建硅基电子器件中没有类似物的器件（1，2）。石墨烯中的传导带和价带形成圆锥形的谷，在称为狄拉克点的点处接触。在布里渊区有两个不等价的狄拉克点，它们通过时间反演对称性联系在一起。纯样品（3-5）的谷间散射受到抑制。谷自由度的独立性和简并性表明，它可能被用来控制电子设备（6），就像电子自旋被用于自旋电子学（7）或量子计算（8）一样。“谷电子学”的一个关键因素是一种可控的方式，可以占据石墨烯中的单个谷，从而产生谷极化。在这里，我们提出了这样一个谷过滤器，基于弹道点接触锯齿形边缘。通过将栅极电压局部施加到点接触区域，可以反转极性。串联的两个谷滤波器可以用作静电控制的谷阀，表示与熟悉的自旋阀对应的零磁场。
The potential of graphene for carbon electronics rests on the possibilities offered by its unusual band structure to create devices that have no analogue in silicon-based electronics(1,2). Conduction and valence bands in graphene form conically shaped valleys, touching at a point called the Dirac point. There are two inequivalent Dirac points in the Brillouin zone, related by time-reversal symmetry. Intervalley scattering is suppressed in pure samples(3-5). The independence and degeneracy of the valley degree of freedom suggests that it might be used to control an electronic device(6), in much the same way as the electron spin is used in spintronics(7) or quantum computing(8). A key ingredient for 'valleytronics' would be a controllable way of occupying a single valley in graphene, thereby producing a valley polarization. Here we propose such a valley filter, based on a ballistic point contact with zigzag edges. The polarity can be inverted by local application of a gate voltage to the point contact region. Two valley filters in series may function as an electrostatically controlled valley valve, representing a zero-magnetic-field counterpart to the familiar spin valve.