磁场对四端量子波导中电子输运性质的影响

采用模匹配方法，研究了非均匀磁场下开放的四端量子波导中的电子输运性质. 结果表明，从一端入射的电子可以透射到两个与之垂直的输出端和一个与之平行的输出端. 在没有外加磁场的情况下，两个垂直输出端的输运概率是相同的，但垂直端与水平端的输运概率不同；在外加磁场下，由于磁边缘态效应，两个垂直输出端的输运概率也有着相当大的差别. 通过施加不同的磁场，我们能获得丰富的电子输运结构，如台阶，宽谷，尖峰等；通过调节磁场的大小和比例以及结构参数可控制该量子结构在各输出端的输运概率. 关键词： 电子输运 介观体系 磁效应

Effect of magnetic field on the transmission properties of electrons in a four-terminal quantum waveguide

We investigate the quantum-mechanical transmission of electrons in a four-terminal quantum waveguide (FTQW) subjected to an inhomogeneous magnetic field perpendicular to the FTQW plane with the use of the mode-matching technique. An electron incident through one channel of the waveguide can travel into the other three channels in the quantum ballistic regime. The results show that in zero field the transmission coefficients in two channels perpendicular to the main wire are of similar behavior, but different from that of the channel parallel to the main wire. However, in an applied magnetic field, the transmission coefficients in two channels perpendicular to the main wire exhibit quite difference from each other and depend sensitively on geometric parameters. When different magnetic configurations are applied in the structure, the transmission exhibits various patterns such as step drop, wide valley, sharp peak, and so on. Our results show that one may control the transmission property of the FTQW to match practical requirements in devices by adjusting magnetic configurations or structural parameters.