Aharonov-Bohm干涉仪中的电子输运

Electronic Transport Properties of the Aharonov-Bohm Interferometer

利用非平衡格林函数技术,我们研究了在Aharonov-Bohm干涉仪中Andreev反射产生的量子输运特性.我们发现Andreev电流可以用一个入射电子经不同通道的Andreev反射概率来表示,并且Andreev电流有两种振荡周期(h/e和h/2e),这个物理原因是不同通道的入射电子的Andreev反射过程的干涉.通过调节系统参数(如量子点的门电压和系统的磁通等),我们可以得到非常尖锐的Andreev电流的共振峰和反共振谷,这个结果可用来设计敏感的Andreev电流开关.

Using the nonequilibrium Green＇ s function technique, we investigate quantum transport properties of an Aharonov-Bohm interferometer due to Andreev reflections. It is found that the Andreev current can be expressed as a result of the mutual interference of different Andreev reflected paths of an incoming electron traversing the interferometer, and the Andreev current exhibits two periods of oscillations（h/e and h/2e）. By adjusting systematic parameters, such as the gate voltages of the quantum dots and the magnetic flux φ in the interferometer, we can obtain extremely narrow resonant current peak and antiresonance current dip. This result provides a mechanism for a very sensitively controlled Andreev current switch.