Departement Fysica, Universiteit Antwerpen, Antwerpen, Belgium.
J Phys Condens Matter. 2010 Nov 24;22(46):465302. doi: 10.1088/0953-8984/22/46/465302. Epub 2010 Nov 4.
We consider a one-dimensional (1D) superlattice (SL) on graphene consisting of very high and very thin (δ-function) magnetic and potential barriers with zero average potential and zero magnetic field. We calculate the energy spectrum analytically, study it in different limiting cases, and determine the condition under which an electron beam incident on an SL is highly collimated along its direction. In the absence of the magnetic SL the collimation is very sensitive to the value of W/W(s) and is optimal for W/W(s) = 1, where W is the distance between the positive and negative barriers and L = W + W(s) is the size of the unit cell. In the presence of only the magnetic SL the collimation decreases and the symmetry of the spectrum around k(y) is broken for W/W(s) ≠ 1. In addition, a gap opens which depends on the strength of the magnetic field. We also investigate the effect of spatially separated potential and magnetic δ-function barriers and predict a better collimation in specific cases.
我们考虑一个由非常高和非常薄（δ 函数）的磁性和势垒组成的石墨烯一维（1D）超晶格（SL），其平均势和磁场均为零。我们对能谱进行了分析计算，研究了不同的极限情况，并确定了电子束入射到 SL 时沿其方向高度准直的条件。在没有磁性 SL 的情况下，准直对 W/W(s)的值非常敏感，并且在 W/W(s) = 1 时达到最佳，其中 W 是正负势垒之间的距离，L = W + W(s)是单元的大小。在只有磁性 SL 的情况下，准直度降低，并且在 W/W(s)≠1 时，谱在 k(y)周围的对称性被破坏。此外，还会出现一个取决于磁场强度的间隙。我们还研究了空间分离的势和磁 δ 函数势垒的影响，并在特定情况下预测了更好的准直度。
