Recent experiments on twisted bilayer graphene have shown a high-temperature parent state with massless Dirac fermions and broken electronic flavor symmetry; superconductivity and correlated insulators emerge from this parent state at lower temperatures. We propose that the superconducting and correlated insulating orders are connected by Wess–Zumino–Witten terms, so that defects of one order contain quanta of another order and skyrmion fluctuations of the correlated insulator are a “mechanism” for superconductivity. We present a comprehensive listing of plausible low-temperature orders and the parent flavor symmetry-breaking orders. The previously characterized topological nature of the band structure of twisted bilayer graphene plays an important role in this analysis.

最近对扭曲双层石墨烯的实验显示出具有无质量狄拉克费米子和电子风味对称性破缺的高温母态；超导性和相关绝缘体在较低温度下从这种母态出现。我们提出超导级和相关绝缘级通过Wess-Zumino-Witten项连接，因此一个级的缺陷包含另一级的量子，并且相关绝缘体的斯格明子涨落是超导性的“机制”。我们提供了合理的低温订单和父风味对称破缺订单的综合列表。先前表征的扭曲双层石墨烯能带结构的拓扑性质在此分析中起着重要作用。