论文标题
扭曲双层石墨烯中的应变障碍和无间隙间隔相干阶段
Strain Disorder and Gapless Intervalley Coherent Phase in Twisted Bilayer Graphene
论文作者
论文摘要
相关的绝缘子经常以魔术角扭曲的双层石墨烯在每个moiré单位电池的均匀填充物上观察到。尽管理论预测这些绝缘子为间隔相干激发阶段，但测得的间隙通常比理论估计值小得多。我们探讨了随机应变变化对Intervalley相干阶段的影响，该相具有类似于超导体磁性障碍的成对效应。我们发现，即使维持间隔相干性，频谱差距也可能被应变障碍或完全消失。我们讨论了状态的隧道密度的预测特征，表明在运输实验中测得的激活差距对应于差异的减少，因此为理论和实验差距之间的明显差异提供了解决方案。
Correlated insulators are frequently observed in magic angle twisted bilayer graphene at even fillings of electrons or holes per moiré unit-cell. Whereas theory predicts these insulators to be intervalley coherent excitonic phases, the measured gaps are routinely much smaller than theoretical estimates. We explore the effects of random strain variations on the intervalley coherent phase, which have a pair-breaking effect analogous to magnetic disorder in superconductors. We find that the spectral gap may be strongly suppressed by strain disorder, or vanish altogether, even as intervalley coherence is maintained. We discuss predicted features of the tunneling density of states, show that the activation gap measured in transport experiments corresponds to the diminished gap, and thus offer a solution for the apparent discrepancy between the theoretical and experimental gaps.
