Data files for "Optimizing the Critical Temperature and Superfluid Density of a Metal-Superconductor Bilayer" by Y Zhang et al (2025)

Data for Optimizing the Critical Temperature and Superfluid Density of a Metal-Superconductor Bilayer by Yutan Zhang, Philip M. Dee, Benjamin Cohen-Stead, Thomas A. Maier, Steven Johnston, and Richard Scalettar. Abstract: A promising path to realizing higher superconducting transition temperatures $T_c$ is the strategic engineering of artificial heterostructures. For example, quantum materials exhibiting some but not all of the characteristics necessary for a robust superconducting state could, in principle, be coupled with other materials in a way that alleviates their intrinsic shortcomings. In this work, we add numerical support to the hypothesis that a strongly interacting superconductor weakened by phase fluctuations can boost its $T_c$ by hybridizing the system with a metal. Using determinant quantum Monte Carlo (DQMC), we simulate a two-dimensional bilayer composed of an attractive Hubbard model and a metallic layer in two regimes of the interaction strength −|𝑈|. In the strongly interacting regime, we find that increasing the interlayer hybridization \tperp results in a nonmonotonic enhancement of $T_c$, with an optimal value comparable to the maximum $T_c$ observed in the single-layer attractive Hubbard model, confirming trends inferred from other approaches. In the intermediate coupling regime, when −|𝑈| is close to the value associated with the maximum $T_c$ of the single-layer model, increasing \tperp tends to decrease $T_c$, implying that the correlated layer was already optimally tuned. Importantly, we demonstrate that the mechanism behind these trends is related to enhancement in the superfluid stiffness, as was initially proposed by Kivelson [Physica B: Condensed Matter 318 , 61 (2002)]. Reference: Y. Zhang et al., Physical Review B (2025). DOI: https://journals.aps.org/prb/accepted/10.1103/lcgr-bqcv Preprint: https://arxiv.org/abs/2501.15428用于优化金属-超导体双层结构临界温度与超流密度的数据集，作者：张宇坦、Philip M. Dee、Benjamin Cohen-Stead、Thomas A. Maier、Steven Johnston 及 Richard Scalettar。 摘要：实现更高超导转变温度（superconducting transition temperature, $T_c$）的极具前景的路径之一，是对人工异质结构开展策略性工程设计。原则上，可将仅具备稳健超导态所需部分（而非全部）特征的量子材料与其他材料耦合，以弥补其固有缺陷。本研究为下述假说提供了数值支撑：若强相互作用超导体因相位涨落被削弱，可通过将其与金属层杂化来提升$T_c$。我们采用行列式量子蒙特卡洛（determinant quantum Monte Carlo, DQMC）方法，在两种相互作用强度$-|U|$的区间下，对由吸引哈伯德模型（attractive Hubbard model）层与金属层构成的二维双层结构进行模拟。在强相互作用区间，我们发现增大层间杂化强度会使$T_c$呈现非单调增强，其最优值与单层吸引哈伯德模型中观测到的最大$T_c$相当，验证了其他方法推导得出的趋势。在中等耦合区间，当$-|U|$接近与单层模型最大$T_c$对应的取值时，增大层间杂化强度往往会降低$T_c$，这表明关联层已处于最优调谐状态。尤为重要的是，我们证明了上述趋势背后的机制与超流刚度的增强有关，这与Kivelson最初提出的假说一致[Physica B: Condensed Matter 318, 61 (2002)]。 参考文献：Y. Zhang等，《物理评论B》(2025)。 DOI：https://journals.aps.org/prb/accepted/10.1103/lcgr-bqcv 预印本：https://arxiv.org/abs/2501.15428