Cheng Shu-Guang
Department of Physics, Northwest University, Xi'an 710069, People's Republic of China. Shaanxi Key Laboratory for Theoretical Physics Frontiers, Xi'an 710069, People's Republic of China.
J Phys Condens Matter. 2018 Apr 25;30(16):165301. doi: 10.1088/1361-648X/aab5e1. Epub 2018 Mar 12.
The electronic transport of graphene p-n junctions under perpendicular magnetic field is investigated in theory. Under low magnetic field, the transport is determined by the resonant tunneling of Landau levels and conductance versus magnetic field shows a Shubnikov-de Haas oscillation. At higher magnetic field, the p-n junction subjected to the quasi-classical regime and the formation of snake states results in periodical backscattering and transmission as magnetic field varies. The conductance oscillation pattern is mediated both by magnetic field and the carrier concentration on bipolar regions. For medium magnetic field between above two regimes, the combined contributions of resonant tunneling, snake states oscillation and Aharanov-Bohm interference induce irregular oscillation of conductance. At very high magnetic field, the system is subjected to quantum Hall regime. Under disorder, the quantum tunneling at low magnetic field is slightly affected and the oscillation of snake states at higher magnetic field is suppressed. In the quantum Hall regime, the conductance is a constant as predicted by the mixture rule.
从理论上研究了垂直磁场下石墨烯 p-n 结的电子输运。在低磁场下，输运由朗道能级的共振隧穿决定，电导随磁场的变化呈现舒布尼科夫-德哈斯振荡。在较高磁场下，处于准经典 regime 的 p-n 结以及蛇形态的形成导致随着磁场变化出现周期性的背散射和透射。电导振荡模式由磁场和双极区域上的载流子浓度共同介导。对于上述两种 regime 之间的中等磁场，共振隧穿、蛇形态振荡和阿哈罗诺夫-玻姆干涉的综合作用导致电导出现不规则振荡。在非常高的磁场下，系统处于量子霍尔 regime。在无序情况下，低磁场下的量子隧穿受到轻微影响，较高磁场下蛇形态的振荡受到抑制。在量子霍尔 regime 中，电导如混合规则所预测的那样是一个常数。
