论文标题
扭曲的多层节点超导体
Twisted multilayer nodal superconductors
论文作者
论文摘要
最近提出，淋巴结超导体的扭曲双层是一个有前途的平台，以容纳自发打破时间反转对称性的超导相。在这里，我们将此分析扩展到扭曲的多层，重点是两个具有交替（$ \pmθ$）和常数（$θ$）扭曲角的高对称性堆叠。与交替的多层石墨烯类似，前者可以映射到具有重新归一化的层间耦合的扭曲的双层，当$ l $的层$ l $奇怪时，也可以与残留的无间隙单层映射。相比之下，后者表现出扭曲的双层超出扭曲的双层物理学，包括当$ l \ mod 4 = 3 $时以立方带交叉的特征的“魔法角度”。由于其幂律的分歧密度，此类多层非常容易受到次要不稳定性的影响。在BCS平均场理论（在连续体和晶格中定义）中，我们发现两个堆叠均寄主的手性手性拓扑超导在其相图的扩展区域中。
Twisted bilayers of nodal superconductors were recently proposed as a promising platform to host superconducting phases that spontaneously break time-reversal symmetry. Here we extend this analysis to twisted multilayers, focusing on two high-symmetry stackings with alternating ($\pm θ$) and constant ($θ$) twist angles. In analogy to alternating-twist multilayer graphene, the former can be mapped to twisted bilayers with renormalized interlayer couplings, along with a remnant gapless monolayer when the number of layers $L$ is odd. In contrast, the latter exhibits physics beyond twisted bilayers, including the occurrence of `magic angles' characterized by cubic band crossings when $L \mod 4 = 3$. Owing to their power-law divergent density of states, such multilayers are highly susceptible to secondary instabilities. Within a BCS mean-field theory, defined in the continuum and on a lattice, we find that both stackings host chiral topological superconductivity in extended regions of their phase diagrams.
