论文标题
当地的kekulé扭曲将扭曲的双层石墨烯变成拓扑莫特绝缘体和超导体
Local Kekulé distortion turns twisted bilayer graphene into topological Mott insulators and superconductors
论文作者
论文摘要
魔术角扭曲的双层石墨烯在充电中立的四个平坦带的不同填充物处显示出许多著名的阶段，其中包括磁性磁绝缘子，其磁化强度主要是轨道性质和连续的超导域。此处通过库仑排斥的正相互作用以及电子耦合到两倍的光学模式来解释这种丰富的相图，该模式对应于位于Moiré超级电池的小AA堆叠区域中的Kekulè扭曲。静态失真可以稳定，在任何整数填充平面带填充物，价值键绝缘子，这些绝缘子将有限的Chern数远离电荷中立。同样，在两个晶格振动之间产生共鸣的动态失真会导致与内置手性D波对的共鸣键 - 键绝缘子的拓扑绝缘子，具有有限的Chern数量等于角动量，因此很容易在掺杂杂物填充物时转动超导。
Magic-angle twisted bilayer graphene displays at different fillings of the four flat bands lying around the charge neutrality point a wealth of notable phases that include magnetic Chern insulators, whose magnetization is mostly of orbital nature, and contiguous superconducting domes. Such rich phase diagram is here explained through the positive interplay of Coulomb repulsion and the electron coupling to a twofold optical mode that corresponds to Kekulè distortions localized into the small AA stacked regions of the moiré supercells. A static distortion stabilizes, at any integer filling of the flat bands, valence-bond insulators that carry finite Chern number away from charge neutrality. Similarly, a dynamic distortion that resonates between the two lattice vibrations leads to resonating-valence-bond topological insulators with built-in chiral d-wave pairs that have finite Chern number equal to the angular momentum, and thus are prone to turn superconducting upon doping away from integer filling.
