Huang Beibing, Yang Xiaosen, Zhang Qinfang, Xu Ning
Department of Physics, Yancheng Institute of Technology, Yancheng, 224051, People's Republic of China.
Department of physics, Jiangsu University, Zhenjiang, 212013, People's Republic of China.
J Phys Condens Matter. 2022 Jan 4;34(11). doi: 10.1088/1361-648X/ac4531.
The antiferromagnetic topological insulator (AFTI) is topologically protected by the combined time-reversal and translational symmetryTc. In this paper we investigate the effects of the-wave superconducting pairings on the multilayers of AFTI, which breaksTcsymmetry and can realize quantum anomalous Hall insulator with unit Chern number. For the weakly coupled pairings, the system corresponds to the topological superconductor (TSC) with the Chern number= ±2. We answer the following questions whether the local Chern numbers and chiral Majorana edge modes of such a TSC distribute around the surface layers. By the numerical calculations based on a theoretic model of AFTI, we find that when the local Chern numbers are always dominated by the surface layers, the wavefunctions of chiral Majorana edge modes must not localize on the surface layers and show a smooth crossover from spatially occupying all layers to only distributing near the surface layers, similar to the hinge states in a three dimensional second-order topological phases. The latter phase, denoted by the hinged TSC, can be distinguished from the former phase by the measurements of the local density of state. In addition we also study the superconducting vortex phase transition in this system and find that the exchange field in the AFTI not only enlarges the phase space of topological vortex phase but also enhances its topological stability. These conclusions will stimulate the investigations on superconducting effects of AFTI and drive the studies on chiral Majorana edge modes and vortex Majorana zero modes into a new era.
反铁磁拓扑绝缘体（AFTI）由时间反演和平移对称性Tc共同提供拓扑保护。在本文中，我们研究了s波超导配对对AFTI多层结构的影响，这种配对打破了Tc对称性，并能实现具有单位陈数的量子反常霍尔绝缘体。对于弱耦合配对，该系统对应于陈数为±2的拓扑超导体（TSC）。我们回答了以下问题：这样一个TSC的局域陈数和手性马约拉纳边缘模是否分布在表面层周围。通过基于AFTI理论模型的数值计算，我们发现，当局域陈数总是由表面层主导时，手性马约拉纳边缘模的波函数一定不会局域在表面层，而是呈现出从空间占据所有层到仅分布在表面层附近的平滑转变，类似于三维二阶拓扑相中的棱态。后一种相，即铰链式TSC，可以通过局域态密度的测量与前一种相区分开来。此外，我们还研究了该系统中的超导涡旋相变，发现AFTI中的交换场不仅扩大了拓扑涡旋相的相空间，还增强了其拓扑稳定性。这些结论将激发对AFTI超导效应的研究，并推动对手性马约拉纳边缘模和涡旋马约拉纳零模的研究进入一个新时代。
