Sacépé B, Seidemann J, Gay F, Davenport K, Rogachev A, Ovadia M, Michaeli K, Feigel’man MV. Low-temperature anomaly in disordered superconductors near
B c2 as a vortex-glass property.
Nat Phys 2019;
15:48-53. [PMID:
30613207 PMCID:
PMC6314456 DOI:
10.1038/s41567-018-0294-6]
[Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 08/28/2018] [Indexed: 06/09/2023]
Abstract
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 B c2 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 B c2 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.
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