标题： 多带超导性和高临界电流密度在熵稳定Nb0.25Ta0.25Ti0.25Zr0.25中 显示英文标题

标题： Multiband Superconductivity and High Critical Current Density in Entropy Stabilized Nb0.25Ta0.25Ti0.25Zr0.25

摘要： 高熵和中熵超导体具有显著的本征无序，是一类引人入胜的超导体。 它们结合了坚固的结构完整性、优越的机械性能和卓越的辐照耐受性，使其成为先进超导技术中的有前途的候选材料。 本文中，我们对等原子量熵稳定Nb0.25Ta0.25Ti0.25Zr0.25的超导性进行了全面的理论和实验研究。 该材料表现出体超导性（转变温度=8K），具有高达11.94T的上临界磁场。 有趣的是，电子能带结构和比热数据均指向非常规多带超导性。 我们的第一性原理计算揭示了接近费米能级的类似狄拉克的能带交叉，某些简并性即使在自旋轨道耦合存在的情况下仍然存在，表明拓扑电子态与观察到的非常规超导性之间可能存在相互作用。 值得注意的是，临界电流密度超过了10^5 A/cm2的基准值，超过了所有之前报道的铸态熵稳定超导体。 这种高的临界电流密度可能是由于晶界处的强通量钉扎，这由极端的本征晶格畸变所促进。 综上所述，所展示的动力学稳定性、优异的金属性、承载非常规超导性的潜力以及异常高的临界电流密度，突显了熵稳定合金作为探索无序、拓扑和非常规超导性交汇点的平台的潜力。 显示英文摘要

摘要： High and medium-entropy superconductors with significant intrinsic disorder are a fascinating class of superconductors. Their combination of robust structural integrity, superior mechanical properties, and exceptional irradiation tolerance makes them promising candidates for use in advanced superconducting technologies. Herein, we present a comprehensive theoretical and experimental investigation on the superconductivity of equiatomic entropy-stabilized Nb0.25Ta0.25Ti0.25Zr0.25. The material shows bulk superconductivity (transition temperature = 8K) with a high upper critical field of 11.94T. Interestingly, both the electronic band structure and specific heat data point toward unconventional multiband superconductivity. Our ab initio calculations reveal Dirac-like band crossings close to the Fermi level, with certain degeneracies persisting even in the presence of spin-orbit coupling, suggesting a possible interplay between topological electronic states and the observed unconventional superconductivity. Remarkably, the critical current density exceeds the benchmark of 10^5 A/cm2, surpassing all previously reported as-cast entropy-stabilized superconductors. This high critical current density is likely attributed to strong flux pinning at the grain boundaries, facilitated by extreme intrinsic lattice distortion. Taken together, the demonstrated dynamical stability, excellent metallicity, potential to host unconventional superconductivity, and exceptionally high critical current density highlight the potential of entropy-stabilized alloys as a platform for exploring the confluence of disorder, topology, and unconventional superconductivity.