双层石墨烯非对称波导中导模性质的分析

研究了基于双层石墨烯的非对称量子阱波导中导模的性质。当石墨烯中电子的入射能一定时，通过控制加在石墨烯不同区域的直流电压，可使狄拉克费米子在非对称波导中存在三种不同类型的运动方式，即准经典运动、量子克莱恩隧穿以及二者的混合运动。在解析推导出导模色散关系的基础上，详细讨论了三种不同情形下导模的结构特征。该研究结果对于石墨烯波导器件的实际应用具有重要意义。

Analysis on characteristics of guided modes in bilayer graphene-based asymmetric waveguides

Based on the Hamiltonian of carriers in bilayer graphene, the characteristic of the guided modes in asymmetric quantum-well waveguides is investigated. There exist three different kinds of motions depending on the incident energy of the electrons and the external potentials, i. e., quasi-classical motion, quantum Klein tunneling, and mixing of the former two. Given the wave functions for the different regions and using the continuity conditions at the interfaces of the potential barriers, the dispersion relationship for the guided modes in asymmetric waveguides is derived analytically. Meanwhile, the structure feature of the guided modes under three different cases is discussed. The study is very significant for the practical applications of graphene-based waveguide devices.