论文标题
Moiré-Hubbard模型的量子相图
Quantum Phase Diagram of a Moiré-Hubbard Model
论文作者
论文摘要
我们从理论上研究了扭曲双层的Moiré超晶格上的广义哈伯德模型，并找到了通过相互作用强度和扭曲角度调节的非常丰富的填充因子依赖性量子相图。 Moiré-Hubbard模型中强的远程库仑相互作用可在一系列分数填充因子处诱导Wigner晶体。 Wigner晶体的有效晶格由填充因子控制，并且可以是三角形，矩形，蜂窝，kagome等，提供了一个平台，通过简单地调整载波密度来实现各种晶格上的许多不同的自旋模型。除了在拓扑上是微不足道的Wigner晶体，相互作用诱导的Chern绝缘子在相图中出现。这一发现铺平了一种工程相互作用诱导的量子异常大厅效应的方式，其中相应的单粒子moiré频带在拓扑上是微不足道的。
We theoretically study a generalized Hubbard model on moiré superlattices of twisted bilayers, and find very rich filling-factor-dependent quantum phase diagrams tuned by interaction strength and twist angle. Strong long-range Coulomb interaction in the moiré-Hubbard model induces Wigner crystals at a series of fractional filling factors. The effective lattice of the Wigner crystal is controlled by the filling factor, and can be triangle, rectangle, honeycomb, kagome, etc, providing a single platform to realize many different spin models on various lattices by simply tuning carrier density. In addition to Wigner crystals that are topologically trivial, interaction-induced Chern insulators emerge in the phase diagram. This finding paves a way for engineering interaction-induced quantum anomalous Hall effect in moiré-Hubbard systems where the corresponding single-particle moiré band is topologically trivial.
