论文标题
扭曲的双层蜂窝磁铁中的镁角状态
Magnon corner states in twisted bilayer honeycomb magnets
论文作者
论文摘要
搜索高阶拓扑绝缘子，其特征在于，以拓扑保护的无间隙边界状态高于高于1的无间隙边界状态，这引起了人们日益增长的兴趣。在这里，我们建立了扭曲的双层蜂窝磁铁，作为一个新的平台，用于托管二阶拓扑镁绝缘子（SOTMIS），而无需进行微调。我们采用一个简单的，最小的Heisenberg自旋模型来描述具有较大相应扭曲角度的蜂窝铁磁磁铁的未对准双层板。我们发现，该双层系统中的高阶拓扑表现出对层间交换耦合的显着依赖性。 SOTMI具有拓扑保护的镁角状态，出现用于铁磁层中膜耦合，而扭曲的双层在抗铁磁性层中耦合的情况下表现出淋巴结相。
Search for higher-order topological insulators, characterized by topologically protected gapless boundary states of codimension higher than one, in bosonic systems has attracted growing interest. Here, we establish twisted bilayer honeycomb magnets as a new platform for hosting second-order topological magnon insulators (SOTMIs) without fine-tuning. We employ a simple, minimal Heisenberg spin model to describe misaligned bilayer sheets of honeycomb ferromagnetic magnets with a large commensurate twist angle. We found that the higher-order topology in this bilayer system shows a significant dependence on the interlayer exchange coupling. The SOTMI, featuring topologically protected magnon corner states, appears for ferromagnetic interlayer couplings, while the twisted bilayer exhibits a nodal phase in the case of antiferromagnetic interlayer coupling.
