Fluctuation spectroscopy of disordered two-dimensional superconductors

Article

关键词: HIGH-TC SUPERCONDUCTORS;    STRONG MAGNETIC-FIELD;    INSULATOR TRANSITION;    QUANTUM CORRECTIONS;    TIN FILMS;    CONDUCTIVITY;    MAGNETORESISTANCE;    TEMPERATURE;    RESISTANCE;    SYSTEMS;   

DOI  :  10.1103/PhysRevB.84.104510

来源: SCIE

【 摘 要 】

We revise the long-studied problem of fluctuation conductivity (FC) in disordered two-dimensional superconductors placed in a perpendicular magnetic field by finally deriving the complete solution in the temperature-magnetic field phase diagram. The obtained expressions allow both to perform straightforward (numerical) calculation of the FC surface delta sigma((tot))(xx)(T, H) and to get asymptotic expressions in all its qualitatively different domains. This surface becomes in particular nontrivial at low temperatures, where it is trough-shaped with delta sigma((tot))(xx)(T, H) < 0. In this region, close to the quantum-phase transition, delta sigma((tot))(xx)(T, H = const) is nonmonotonic, in agreement with experimental findings. We reanalyzed and present comparisons to several experimental measurements. Based on our results we derive a qualitative picture of superconducting fluctuations close to H-c2(0) and T = 0 where fluctuation Cooper pairs rotate with cyclotron frequency omega(c) similar to Delta(-1)(BCS) and Larmor radius similar to xi(BCS), forming some kind of quantum liquid with long coherence length xi(QF) >> xi(BCS) and slow relaxation (tau(QF) >> (h) over bar Delta(-1)(BCS)).

【 授权许可】

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