论文标题
WSE稳定的扭曲双双层石墨烯中的超导率$ _2 $
Superconductivity in Twisted Double Bilayer Graphene Stabilized by WSe$_2$
论文作者
论文摘要
以前已经在单层石墨烯的魔角扭曲的堆叠中观察到了超导性，但在双层石墨烯的扭曲堆栈中并不明显，尽管这两个系统都有托有拓扑平面频带和对称性旋转状态。在这里，我们报告了与WSE $ _2 $接近的扭曲双双层石墨烯（TDBG）中超导性的发现。带有扭曲角的样品1.24 $^\ circ $和1.37 $^\ circ $超导体分别在栅极和传导带中的栅极调整相图的小口袋中。超导性来自范霍夫（Van Hove）奇异点附近的未极化状态，以及旁边的同胞对称性损坏的区域，显示了高密度的状态与TDBG中超导性的出现之间的相关性，同时揭示了配对中同质素波动的可能作用。
Superconductivity has been previously observed in magic-angle twisted stacks of monolayer graphene but conspicuously not in twisted stacks of bilayer graphene, although both systems host topological flat bands and symmetry-broken states. Here, we report the discovery of superconductivity in twisted double bilayer graphene (TDBG) in proximity to WSe$_2$. Samples with twist angles 1.24$^\circ$ and 1.37$^\circ$ superconduct in small pockets of the gate-tuned phase diagram within the valence and conduction band, respectively. Superconductivity emerges from unpolarized states near van Hove singularities and next to regions with broken isospin symmetry, showing the correlation between a high density of states and the emergence of superconductivity in TDBG while revealing a possible role for isospin fluctuations in the pairing.
