Robust Majorana bound states in magnetic topological insulator nanoribbons with fragile chiral edge channels
Robust Majorana bound states in magnetic topological insulator nanoribbons with fragile chiral edge channels
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DOI：
10.1103/physrevb.109.045138
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发表时间：
2023-02
影响因子：
3.7
通讯作者：
D. Burke;Dennis Heffels;K. Moors;P. Schuffelgen;D. Grutzmacher;M. Connolly
中科院分区：
文献类型：
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作者：
D. Burke;Dennis Heffels;K. Moors;P. Schuffelgen;D. Grutzmacher;M. Connolly
量子反常霍尔机制中的磁性拓扑绝缘体拥有弹道手性边缘通道。当接近的$s$波超导体，这些边缘状态提供了实现拓扑超导性和马约拉纳束缚态的潜力，而不会对超导性的大的外部施加的磁场的不利影响。实现良好分离的未成对的马约拉纳束缚态需要磁性拓扑绝缘体带的边缘状态的横向范围的顺序的宽度，然而，这预计将使所需的带宽度下降到约100 nm。在这种情况下，已知极难保持手性边缘通道的弹道性质并实现量子化霍尔电导。在本文中，我们研究了这种磁性拓扑绝缘体纳米带中的无序的影响，并比较了当带被超导膜覆盖时，弹道手征边缘通道的脆弱性与马约拉纳束缚态的稳定性。我们发现，马约拉纳束缚态表现出更大的鲁棒性对混乱比潜在的手征边缘通道。
Magnetic topological insulators in the quantum anomalous Hall regime host ballistic chiral edge channels. When proximitized by an $s$-wave superconductor, these edge states offer the potential for realizing topological superconductivity and Majorana bound states without the detrimental effect of large externally-applied magnetic fields on superconductivity. Realizing well-separated unpaired Majorana bound states requires magnetic topological insulator ribbons with a width of the order of the transverse extent of the edge state, however, which is expected to bring the required ribbon width down to around 100 nm. In this regime, it is known to be extremely difficult to retain the ballistic nature of chiral edge channels and realize a quantized Hall conductance. In this paper, we study the impact of disorder in such magnetic topological insulator nanoribbons and compare the fragility of ballistic chiral edge channels with the stability of Majorana bound states when the ribbon is covered by a superconducting film. We find that the Majorana bound states exhibit greater robustness against disorder than the underlying chiral edge channels.