论文标题
MoiréChern绝缘子中的成像轨道铁磁
Imaging orbital ferromagnetism in a moiré Chern insulator
论文作者
论文摘要
Moiré平面系统中的电子可以自发打破时间逆转对称性，从而产生量化的异常效果。在这里，我们使用一个超导量子干扰装置来图像在一个系统中，由扭曲的双层石墨烯组成的系统中，与六边形的硝化硼对齐。我们发现每个电荷载体的几个Bohr磁子的磁化强度，表明磁性主要是轨道本质上的。我们的测量结果表明，磁化强度发生了很大的变化，因为化学电位横扫了量子异常的大厅间隙，这与手性边缘状态对轨道Chern绝缘子磁化的预期贡献一致。绘制了场驱动的磁反转的空间演化，我们找到了一系列可再现的微米尺度域，其边界构成了手性边缘状态。
Electrons in moiré flat band systems can spontaneously break time reversal symmetry, giving rise to a quantized anomalous Hall effect. Here we use a superconducting quantum interference device to image stray magnetic fields in one such system composed of twisted bilayer graphene aligned to hexagonal boron nitride. We find a magnetization of several Bohr magnetons per charge carrier, demonstrating that the magnetism is primarily orbital in nature. Our measurements reveal a large change in the magnetization as the chemical potential is swept across the quantum anomalous Hall gap consistent with the expected contribution of chiral edge states to the magnetization of an orbital Chern insulator. Mapping the spatial evolution of field-driven magnetic reversal, we find a series of reproducible micron scale domains whose boundaries host chiral edge states.
