Resistance anomalies in superconducting mesoscopic Al structures

Abstract

We present a detailed study of the recently reported resistance peaks close to the superconducting transition of quasi-one-dimensional mesoscopic Al structures. It is found that the anomalies can be induced by radiofrequency irradiation or by applying sufficiently high dc currents. The nonmonotonic resistance curves are correlated with excess voltages in the voltage-current characteristics close to the critical current and depend strongly on the temperature and the magnetic field. The experimental results can be qualitatively understood in terms of charge imbalance around phase-slip centers which nucleate at particular spots in the sample with a locally reduced transition temperature.

Metal–Bosonic Insulator–Superconductor Transition in Boron-Doped Granular Diamond

“…With the discovery of quasi-2D cuprates, the RðTÞ peak around T c was also reported for these lowdimensional materials, such as NdCeCuO [7], BiSrCaCuO [8,9], and LaSrCuO [10,11], with the peak amplitude reaching 400%-700%. In 2D and 1D microstructures [6,[12][13][14][15][16], made from conventional superconducting materials (mostly Al), a narrow resistance peak close to T c was also observed, with the peak amplitude reaching the 400% level.Different models were used to explain the nature of the anomalous RðTÞ peak: normal-metal-superconductor boundaries, disorder and fluctuations, vortex dynamics and Josephson coupling in layered systems, charge imbalance, and competition between superconducting and insulating states in 2D systems [1,2,4,6,8,[12][13][14]16,17].All these observations of the RðTÞ peak around T c and the corresponding models and theories, formulated to explain the corresponding experimental data, are very much linked to the reduced dimensionality of the investigated systems: 2D or/and 1D. We have found reports on the RðTÞ peak for 3D-like metallic Cu-Zr glasses only in a couple of previous publications [17,18] with a quite small RðTÞ peak amplitude-less than 3%.…”

“…With the discovery of quasi-2D cuprates, the RðTÞ peak around T c was also reported for these lowdimensional materials, such as NdCeCuO [7], BiSrCaCuO [8,9], and LaSrCuO [10,11], with the peak amplitude reaching 400%-700%. In 2D and 1D microstructures [6,[12][13][14][15][16], made from conventional superconducting materials (mostly Al), a narrow resistance peak close to T c was also observed, with the peak amplitude reaching the 400% level.…”

“…Different models were used to explain the nature of the anomalous RðTÞ peak: normal-metal-superconductor boundaries, disorder and fluctuations, vortex dynamics and Josephson coupling in layered systems, charge imbalance, and competition between superconducting and insulating states in 2D systems [1,2,4,6,8,[12][13][14]16,17].…”

Nonlocal Correlations in Normal-Metal Superconducting Systems

“…[8] The CI contribution vanishes in the limit of low temperatures and low energies, as shown by a number of experiments over the last thirty years. [9,10,11,12,13,14,15] In these experiments, however, the induced charge imbalance was local, in the sense that the nonequilibrium distributions were probed along the current path, as depicted in Fig. 1(c).…”

“…[9,10,14] More recent experiments on charge imbalance are consistent with Λ Q * ∼ 1 µm, in agreement with the values we obtain. [11,15] We can therefore distinguish the EC/CAR contribution to the nonlocal resistance from the CI contribution based its temperature, current and scaling with the distance from the current-carrying NS interface. The EC/CAR contribution at low temperature and zero current-bias is positive, indicating that the magnitude of the EC contribution is larger than that of the CAR contribution, as predicted for transparent NS interfaces.…”