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arXiv 1102.1604cond-mat.supr-concond-mat.dis-nncond-mat.mes-hallcond-mat.str-el
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低维超导体电导和电流的第一性原理计算

First principles calculation of conductance and current flow through low-dimensional superconductors

G. J. Conduit, Yigal Meir

摘要:

我们提出了一种新的配方来计算通过无序超导体之间的两个金属引线连接的输运。导出了电流的精确表达式,并应用于负$U$哈伯德模型描述的超导样品。本文采用了一种包含超导序参量的热相位和振幅涨落的蒙特卡罗算法,并提出了一种新的有效算法。这种改进的例程允许访问相对较大的系统,我们通过将其应用于几种情况(包括超导正常界面和约瑟夫森结)来证明这一点。退相干和退相的影响被示出包括在配方中,它允许明确的表征的Kosterlitz无过渡在二维系统和计算的有限阻力由于涡激准一维系统。磁场的影响可以很容易地包括在形式主义,并证明了超导圆柱体中的Little-Parks效应。此外,形式主义使我们能够映射局部的超级和正常电流,以及伴随的电势,我们使用这些电势来精确定位和可视化超导体-绝缘体过渡中电阻的出现。

英文摘要:

We present a novel formulation to calculate transport through disordered superconductors connected between two metallic leads. An exact expression for the current is derived, and is applied to a superconducting sample described by the negative-$U$ Hubbard model. A Monte Carlo algorithm that includes thermal phase and amplitude fluctuations of the superconducting order parameter is employed, and a new efficient algorithm is described. This improved routine allows access to relatively large systems, which we demonstrate by applying it to several cases, including superconductor-normal interfaces and Josephson junctions. The effects of decoherence and dephasing are shown to be included in the formulation, which allows the unambiguous characterization of the Kosterlitz-Thouless transition in two-dimensional systems and the calculation of the finite resistance due to vortex excitations in quasi one-dimensional systems. Effects of magnetic fields can be easily included in the formalism, and are demonstrated for the Little-Parks effect in superconducting cylinders. Moreover, the formalism enables us to map the local super and normal currents, and the accompanying electrical potentials, which we use to pinpoint and visualize the emergence of resistance across the superconductor-insulator transition.

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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