论文标题
安德森的定理用于扭曲的双层石墨烯中的绝缘状态
Anderson's theorem for correlated insulating states in twisted bilayer graphene
论文作者
论文摘要
魔法扭曲的双层石墨烯中相关的绝缘阶段的出现表现出强烈的样品依赖性。在这里，我们得出了一个安德森定理，负责对Kramers Investalley Coohent（K-IVC）状态的鲁棒性，这是描述Moiré平面带均匀填充物中相关绝缘子的主要候选人。我们发现，K-IVC差距与局部扰动相对强大，在$ \ Mathcal {pt} $下是奇怪的，其中$ \ Mathcal {p} $和$ \ Mathcal {t} $分别表示粒子孔 - 孔 - 孔 - 孔结合和时间逆转。相比之下，$ \ Mathcal {pt} $ - 甚至扰动也一般会诱导子段状态，并减少甚至消除差距。我们使用此结果将K-IVC状态的稳定性分类为各种实验相关的扰动。 Anderson定理的存在从其他可能的绝缘接地状态中删除了K-IVC状态。
The emergence of correlated insulating phases in magic-angle twisted bilayer graphene exhibits strong sample dependence. Here, we derive an Anderson theorem governing the robustness against disorder of the Kramers intervalley coherent (K-IVC) state, a prime candidate for describing the correlated insulators at even fillings of the moiré flat bands. We find that the K-IVC gap is robust against local perturbations, which are odd under $\mathcal{PT}$, where $\mathcal{P}$ and $\mathcal{T}$ denote particle-hole conjugation and time reversal, respectively. In contrast, $\mathcal{PT}$-even perturbations will in general induce subgap states and reduce or even eliminate the gap. We use this result to classify the stability of the K-IVC state against various experimentally relevant perturbations. The existence of an Anderson theorem singles out the K-IVC state from other possible insulating ground states.
