Department of Physics and Key Laboratory of Atomic and Molecular NanoSciences, Ministry of Education, Tsinghua University, Beijing, People's Republic of China.
J Phys Condens Matter. 2010 Nov 10;22(44):445303. doi: 10.1088/0953-8984/22/44/445303. Epub 2010 Oct 22.
We investigate the transmission of electrons in a single layer graphene system subjected to nanoscale magnetic barriers and wells arranged in the Cantor pre-fractal and the finite periodic distribution. We find that the angular threshold and angular asymmetry of the transmission spectra are closely related to the ratio between the magnitude of the vector potential and the incident energy (|A|/E), which also determine the number and width of the resonant domains for the finite periodically magnetic modulation and the splitting features for the pre-fractal distribution. For the finite periodically magnetic modulation, the position, magnitude, and interval of the oscillatory domains in the conductance spectra are determined by the value |A|. However, due to the disorder of the pre-fractal distribution, the oscillation of the conductance spectrum is less regular compared to the corresponding one of the finite periodic distribution. We also find that the conductance approaches the classical limit in the high-Fermi-energy region but exceeds it in the low-Fermi-energy region, and the critical point of the two regions is negatively correlated with the magnitude of the vector potential.
我们研究了在单原子层石墨烯系统中电子的传输，该系统受到了在康托尔分形和有限周期分布中排列的纳米级磁垒和磁阱的影响。我们发现，传输谱的角阈和角非对称性与矢量势的大小与入射能量的比值（|A|/E）密切相关，这也决定了有限周期性磁调制的共振域的数量和宽度以及预分形分布的分裂特征。对于有限周期性磁调制，电导谱中振荡域的位置、幅度和间隔由|A|值决定。然而，由于预分形分布的无序性，与有限周期性分布对应的电导谱的振荡不太规则。我们还发现，在高费米能区域，电导接近经典极限，但在低费米能区域，电导超过经典极限，这两个区域的临界点与矢量势的大小呈负相关。
