压缩应力下铌薄膜中低能隙组分存在的证据
Evidence for a low-gap component in compressively stressed niobium thin films
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中文总结 AI 辅助
本研究通过微波响应测量发现，压缩应力下铌薄膜存在额外低能隙组分，其贡献随应力增加，导致微波损耗增强，而传统输运测量无法察觉此现象。
中文摘要 AI 辅助
我们研究了溅射铌薄膜的微波响应随双轴薄膜应力的变化。尽管输运测量显示整个应力系列中超导转变温度（$9.0\pm 0.2$K）和残余电阻比几乎相同，但由高压缩薄膜制成的微波谐振器表现出增强的温度相关损耗和更大的频移。传统的单相Mattis-Bardeen描述给出的有效临界温度为$2.4\pm0.2$K，比输运测量得到的值低约四倍。我们表明，数据反而与存在一个额外的低能隙组分一致，该组分的贡献随压缩应力的增加而增加。这些结果表明，传统的输运测量可能忽略强烈影响微波性能的应力相关低能激发。
英文摘要
We investigate the microwave response of sputtered Nb films as a function of biaxial film stress. Although transport measurements show nearly identical superconducting transition temperatures ($9.0\pm 0.2$K) and residual resistance ratios across the stress series, microwave resonators fabricated from highly compressive films exhibit enhanced temperature-dependent loss and larger frequency shifts. A conventional single-phase Mattis--Bardeen description yields an effective critical temperature of $2.4\pm0.2$K, approximately a factor of four below the value obtained from transport measurements. We show that the data are instead consistent with the presence of an additional low-gap component whose contribution increases with compressive stress. These results show that conventional transport measurements can overlook stress-dependent low-energy excitations that strongly influence microwave performance.
发表机构
- Syracuse University（雪城大学）
- Cornell University（康奈尔大学）
- University of Wisconsin–Madison（威斯康星大学麦迪逊分校）
机构由 AI 辅助整理，请以论文原文为准。
