Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305.
Department of Applied Physics, Stanford University, Stanford, CA 94305.
Proc Natl Acad Sci U S A. 2022 Jul 19;119(29):e2202496119. doi: 10.1073/pnas.2202496119. Epub 2022 Jul 14.
Resistivity saturation is found on both superconducting and insulating sides of an "avoided" magnetic-field-tuned superconductor-to-insulator transition (H-SIT) in a two-dimensional In/InO composite, where the anomalous metallic behavior cuts off conductivity or resistivity divergence in the zero-temperature limit. The granular morphology of the material implies a system of Josephson junctions (JJs) with a broad distribution of Josephson coupling and charging energy , with an H-SIT determined by the competition between and . By virtue of self-duality across the true H-SIT, we invoke macroscopic quantum tunneling effects to explain the temperature-independent resistance where the "failed superconductor" side is a consequence of phase fluctuations and the "failed insulator" side results from charge fluctuations. While true self-duality is lost in the avoided transition, its vestiges are argued to persist, owing to the incipient duality of the percolative nature of the dissipative path in the underlying random JJ system.
在二维 In/InO 复合材料中，“规避”磁场调谐超导体-绝缘体转变（H-SIT）的超导和绝缘两侧都存在电阻率饱和现象，其中异常金属行为在零温极限下切断电导率或电阻率发散。材料的颗粒形态意味着存在一个约瑟夫森结（JJ）系统，具有约瑟夫森耦合和充电能的广泛分布，H-SIT 由 和 的竞争决定。由于真正的 H-SIT 具有自对偶性，我们利用宏观量子隧道效应来解释与温度无关的电阻，其中“失效的超导体”一侧是相位波动的结果，而“失效的绝缘体”一侧则是电荷波动的结果。虽然真正的自对偶性在规避转变中丢失，但由于基础随机 JJ 系统中耗散路径的渗透性质的初始对偶性，认为其残余仍然存在。
