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arXiv 1407.4474cond-mat.supr-concond-mat.mes-hall
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超导相变时的非平衡噪声和电流涨落

Nonequilibrium noise and current fluctuations at the superconducting phase transition

Dmitry Bagrets, Alex Levchenko

摘要:

研究了介观NSN电路中超导相变点的非高斯非平衡电流涨落。该装置包括一个电压偏置的薄膜纳米桥超导体(S)连接到两个正常的金属(N)通过隧道结引线。我们发现,以上的临界温度波动的超导序参量与预制的库珀对介导的非弹性电子散射,促进强电流波动。虽然电导被抑制由于准粒子态密度的耗尽,更高的累积量的电流波动参数增强。我们确定实验相关的运输制度,过量的电流噪声可能达到甚至超过热噪声的水平。

英文摘要:

We study non-Gaussian out-of-equilibrium current fluctuations in a mesoscopic NSN circuit at the point of a superconducting phase transition. The setup consists of a voltage-biased thin film nanobridge superconductor (S) connected to two normal-metal (N) leads by tunnel junctions. We find that above a critical temperature fluctuations of the superconducting order parameter associated with the preformed Cooper pairs mediate inelastic electron scattering that promotes strong current fluctuations. Though the conductance is suppressed due to the depletion of the quasiparticle density of states, higher cumulants of current fluctuations are parametrically enhanced. We identify experimentally relevant transport regime where excess current noise may reach or even exceed the level of the thermal noise.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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