论文标题
$π$ -Flux Square晶格上的三胞胎对密度波超导性
Triplet Pair-Density Wave Superconductivity on the $π$-flux Square Lattice
论文作者
论文摘要
配对密度波（PDW）是超导状态，它们在具有时间反转对称性（TRS）的系统中自发打破翻译对称性。在最近的几项实验以及铜塔中的伪制度政权中，已经看到了PDW的证据。对PDW的理论理解在很大程度上仅限于现象学和数值研究，而微观理论通常需要强耦合或微调。在这项工作中，我们提供了一种新型的基于对称性的机制，在该机制下，PDW作为2D TRS金属的弱耦合不稳定性出现。结合了平均场和重新归一化组分析，我们确定了弱耦合的不稳定性，即在$π$ -Flux Square晶格模型中实现的三胞胎PDW，当Fermi级别交叉1/4和3/4/4/4/4/4/4/4/4/4/4的填充物时，具有现场排斥和中等最近的邻居吸引力。该PDW受Hofstadter Systems的磁翻译对称性特征保护，其中$π$ -Flux晶格是一种特殊的时间反转对称情况。
Pair-density waves (PDW) are superconducting states that spontaneously break translation symmetry in systems with time-reversal symmetry (TRS). Evidence for PDW has been seen in several recent experiments, as well as in the pseudogap regime in cuprates. Theoretical understanding of PDW has been largely restricted to phenomenological and numerical studies, while microscopic theories typically require strong-coupling or fine-tuning. In this work, we provide a novel symmetry-based mechanism under which PDW emerges as a weak coupling instability of a 2D TRS metal. Combining mean-field and renormalization group analyses, we identify a weak-coupling instability towards a triplet PDW realized in the $π$-flux square lattice model with on-site repulsion and moderate nearest-neighbor attraction when the Fermi level crosses Van Hove singularities at 1/4 and 3/4 fillings. This PDW is protected by the magnetic translation symmetries characteristic of Hofstadter systems, of which the $π$-flux lattice is a special time-reversal symmetric case.
