Direction-dependent tunneling through nanostructured magnetic barriers in graphene
Direction-dependent tunneling through nanostructured magnetic barriers in graphene
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DOI：
10.1103/physrevb.77.235443
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发表时间：
2008-06-01
影响因子：
3.7
通讯作者：
Peeters, F. M.
中科院分区：
文献类型：
--
作者：
Masir, M. Ramezani;Vasilopoulos, P.;Peeters, F. M.
我们评估了石墨烯纳米结构中的磁势垒传输。文中考虑了几种特殊情况：磁步进、单势垒和双势垒以及三角函数势垒。另一类磁障结构是那些磁场分布不均匀的结构，使得平均磁场消失，这可以通过放置在石墨烯层顶部的纳米结构铁磁条来实现。对于磁台阶和一些具有有限宽度势垒的结构，预测了局域在势垒附近或势垒中的量子束缚态，但对于增量函数势垒则没有。当束缚态在势垒边缘附近局域化时，它具有平行于该边缘的非零速度。这种透射率强烈地依赖于入射电子或空穴波矢的方向，并使构造与方向相关的波矢滤波器成为可能。一般来说，对于具有线性光谱的(狄拉克)电子，传输的共振结构比具有抛物线光谱的普通电子明显得多。
We evaluate the transmission through magnetic barriers in graphene-based nanostructures. Several particular cases are considered: a magnetic step, single and double barriers, and delta-function barriers. A separate class of magnetic-barrier structures are those with inhomogeneous magnetic-field profiles, such that the average magnetic field vanishes, which can be realized by nanostructured ferromagnetic stripes placed on top of the graphene layer. Quantum bound states that are localized near or in the barrier are predicted for a magnetic step and some structures with finite-width barriers but none for delta-function barriers. When a bound state is localized close to the barrier edge, it has a nonzero velocity parallel to this edge. The transmission depends strongly on the direction of the incident electron or hole wave vector and gives the possibility to construct a direction-dependent wave vector filter. In general, the resonant structure of the transmission is significantly more pronounced for (Dirac) electrons with linear spectrum than for the usual electrons with a parabolic spectrum.