Robust anomalous metallic states and vestiges of self-duality in two-dimensional granular In-InOx composites
Robust anomalous metallic states and vestiges of self-duality in two-dimensional granular In-InOx composites
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DOI：
10.1038/s41535-021-00329-2
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发表时间：
2021-03
影响因子：
5.7
通讯作者：
Xinyang Zhang;B. Hen;A. Palevski;A. Kapitulnik
中科院分区：
文献类型：
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作者：
Xinyang Zhang;B. Hen;A. Palevski;A. Kapitulnik
许多研究磁场调谐超导体-绝缘体转变（H-SIT）的实验经常表现出低温电阻饱和，这被解释为从“失效超导体”中出现的异常金属相，从而挑战传统理论。在这里，我们研究了生长在氧化铟栅极层上的铟岛的随机颗粒阵列。通过调谐晶粒间耦合，我们揭示了在仔细的电磁滤波条件下和在广泛的线性响应范围内观察到电阻饱和的广泛磁场。暴露于外部宽带噪声或微波辐射可以增强超导倾向，在低场下恢复全局超导相。增加的磁场揭示了一个“避免的H-SIT”，显示出颗粒诱导的电阻/电导率在该转变上方/下方的对数发散，指出了在真正的H-SIT中观察到的原始涌现对偶性的可能痕迹。我们得出结论，异常金属相与固有的不均匀性密切相关，在可达到的温度下，对强颗粒二维系统表现出稳健的行为。
Many experiments investigating magnetic-field tuned superconductor-insulator transition (H-SIT) often exhibit low-temperature resistance saturation, which is interpreted as an anomalous metallic phase emerging from a ‘failed superconductor’, thus challenging conventional theory. Here we study a random granular array of indium islands grown on a gateable layer of indium-oxide. By tuning the intergrain couplings, we reveal a wide range of magnetic fields where resistance saturation is observed, under conditions of careful electromagnetic filtering and within a wide range of linear response. Exposure to external broadband noise or microwave radiation is shown to strengthen the tendency of superconductivity, where at low field a global superconducting phase is restored. Increasing magnetic field unveils an ‘avoided H-SIT’ that exhibits granularity-induced logarithmic divergence of the resistance/conductance above/below that transition, pointing to possible vestiges of the original emergent duality observed in a true H-SIT. We conclude that anomalous metallic phase is intimately associated with inherent inhomogeneities, exhibiting robust behavior at attainable temperatures for strongly granular two-dimensional systems.