Sacépé Benjamin, Seidemann Johanna, Gay Frédéric, Davenport Kevin, Rogachev Andrey, Ovadia Maoz, Michaeli Karen, Feigel'man Mikhail V
Univ. Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, 38000 Grenoble, France.
Department of Physics and Astronomy, University of Utah, Salt Lake City, Utah 84112, USA.
Nat Phys. 2019 Jan;15(1):48-53. doi: 10.1038/s41567-018-0294-6. Epub 2018 Oct 8.
Strongly disordered superconductors in a magnetic field display many characteristic properties of type-II superconductivity-except at low temperatures, where an anomalous linear temperature dependence of the resistive critical field is routinely observed. This behavior violates the conventional theory of superconductivity, and its origin has posed a long-standing puzzle. Here we report systematic measurements of the critical magnetic field and current on amorphous indium oxide films with various levels of disorder. Surprisingly, our measurements show that the anomaly is accompanied by mean-field-like scaling of the critical current. Based on a comprehensive theoretical study we argue that these observations are a consequence of the vortex-glass ground state and its thermal fluctuations. Our theory further predicts that the linear-temperature anomaly occurs more generally in both films and disordered bulk superconductors, with a slope that depends on the normal-state sheet resistance, which we confirm experimentally.
处于磁场中的强无序超导体展现出许多II型超导的特征性质——但在低温下除外，在低温时，电阻临界场的反常线性温度依赖性经常被观测到。这种行为违反了传统超导理论，其起源一直是个长期存在的谜题。在此，我们报告了对具有不同无序程度的非晶氧化铟薄膜的临界磁场和电流的系统测量。令人惊讶的是，我们的测量表明，该反常现象伴随着临界电流的类平均场标度。基于全面的理论研究，我们认为这些观测结果是涡旋玻璃基态及其热涨落的结果。我们的理论进一步预测，线性温度反常现象在薄膜和无序块状超导体中更普遍地出现，其斜率取决于正常态面电阻，我们通过实验证实了这一点。
