石墨烯量子反常霍尔效应体系中的量子干涉效应

Quantum interference in graphene with quantum anomalous hall effect system

为了研究量子边缘态间的干涉效应,以锯齿型石墨烯纳米带为基础,通过引入外部自旋轨道耦合及磁交换场,在石墨烯纳米带中实现量子反常霍尔效应。在此基础上,构造弱耦合量子散射腔,并采用紧束缚近似下的哈密顿模型和非平衡格林函数方法,研究经由2个耦合边界反射的量子边缘态间的量子干涉效应。结果表明:弱磁场下,2个理想的反射边缘态间产生A-B干涉效应,随着磁场的变化,透射系数发生周期性的相长或相消干涉,干涉周期和穿过散射腔的磁通成反比。此外,干涉效应对杂质散射和体态非常敏感。因此,通过观测量子干涉效应可以定性地判断体系是否存在真正的边缘态。

To study characteristics of quantum interference in graphene possessed quantum anomalous Hall effect,graphene has been made into specific structure.With the aid of the tight-binding model and none-equilibrium Green＇s function,the interferences between the quantum anomalous Hall edge states in a graphene based quantum scattering cavity are investigated in the presence of weak magnetic field.The interference period is inversely proportional with flux penetrating the scattering cavity.Furthermore,the interfering effects are sensitive to the disorder scattering and the bulk states.Finally,researches show that quantum interference can be used to measure the edge states in graphene.