标题： 用扫描量子显微镜探测二维超导体中的涡旋动力学 显示英文标题

标题： Probing Vortex Dynamics in 2D Superconductors with Scanning Quantum Microscope

摘要： 二维超导材料在纳米尺度上的磁响应可视化是一种强大的方法，用于揭示潜在的超电流行为，并研究降低维度下的临界现象。 本研究中，利用扫描量子显微镜探索了二维超导体2H-NbSe2的局域磁响应。 我们的技术能够以高灵敏度和高达30纳米的空间分辨率，同时静态和动态地感应超导涡旋，揭示了与超导体固有二维性质相关的一些出乎意料的现象，这些现象用更传统的局域探针难以检测。 涡旋并不排列成六角晶格，而是形成一个膨胀涡旋尺寸的扭曲涡旋玻璃。 由于热激发，涡旋可以表现出强烈的局部动力学。 随着临界温度的接近，可以清楚地识别出涡旋玻璃的熔化，导致在不同冷却条件下出现不同的配置。 通过自旋Hahn-回波测量也可以探测涡旋波动，这揭示了即使在临界温度以下也能观察到的自旋去相干——并且有趣的是，在更低温度下去相干增强。 与涡旋激发和波动相关的磁场动力学的时空显微镜提供了直接证据，证明了纳米尺度上的二维超导现象。 显示英文摘要

摘要： The visualization of the magnetic responses of a two-dimensional (2D) superconducting material on the nanoscale is a powerful approach to unravel the underlying supercurrent behavior and to investigate critical phenomena in reduced dimensions. In this study, scanning quantum microscopy is utilized to explore the local magnetic response of the 2D superconductor 2H-NbSe2. Our technique enables both static and dynamic sensing of superconducting vortices with high sensitivity and a spatial resolution down to 30 nm, unveiling unexpected phenomena linked to the intrinsic 2D nature of the superconductor, which are challenging to detect with more conventional local probes. Vortices do not arrange in a hexagonal lattice, but form a distorted vortex glass with expanding vortex size. A vortex can exhibit strong local dynamics due to thermal excitation. As the critical temperature is approached, a clear melting of the vortex glass is identified, leading to distinct configurations under different cooling conditions. Vortex fluctuations can also be probed through spin Hahn-echo measurements, which reveal the spin decoherence even well below the critical temperature -- and, intriguingly, enhanced decoherence at lower temperatures. Spatiotemporal microscopy of the magnetic dynamics associated with vortex excitations and fluctuations provides direct evidence of 2D superconducting phenomena at the nanoscale.