论文标题
扭曲双层石墨烯中的Skyrmion和Tetarton Lattices
Skyrmion and Tetarton Lattices in Twisted Bilayer Graphene
论文作者
论文摘要
在扭曲的双层石墨烯上进行的最新实验表明，每个Moirè晶胞填充了$ 3 $的电子量的异常量子厅（AQH）效果。 AQH效应以山谷和铁磁顺序同时以绝缘状态产生。我们认为，这种系统的薄弱掺杂导致形成了一种新型的拓扑旋转质地，即“双tetarton晶格”。该晶格的构建块“双tetarton”是一种旋转配置，覆盖了两次单位球的$ 1/4 $。与Skyrmion晶格相反，这种磁纹理的净磁化消失了。只有在大磁场下，恢复了更常规的天空晶格。但是，即使对于大型田地，在铁磁AQH状态中添加了单个电荷也会翻转数百个旋转。我们的分析基于对有效的非线性Sigma模型的研究，该模型包括长期库仑相互作用的影响。
Recent experiments on twisted bilayer graphene show an anomalous quantum Hall (AQH) effect at filling of $3$ electrons per moirè unit cell. The AQH effect arises in an insulating state with both valley- and ferromagnetic order. We argue, that weak doping of such a system leads to the formation of a novel topological spin texture, a `double-tetarton lattice'. The building block of this lattice, the `double-tetarton', is a spin configuration which covers $1/4$ of the unit-sphere twice. In contrast to skyrmion lattices, the net magnetization of this magnetic texture vanishes. Only at large magnetic fields more conventional skyrmion lattices are recovered. But even for large fields the addition of a single charge to the ferromagnetic AQH state flips hundreds of spins. Our analysis is based on the investigation of an effective non-linear sigma model which includes the effects of long-ranged Coulomb interactions.
