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arXiv 1704.03045cond-mat.supr-con
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Josephson磁通流振荡器的微观隧穿方法

Josephson Flux Flow Oscillator: the Microscopic Tunneling Approach

D. R. Gulevich, V. P. Koshelets, F. V. Kusmartsev

摘要:

基于Werthamer的微观隧穿理论,对大约瑟夫森结进行了详细的理论描述。该模型自然地包含了电磁辐射对隧道电流的耦合,因此特别适合于描述约瑟夫森结中的自耦合效应。在我们的数值计算中,我们处理所产生的积分微分方程,它描述了时间演化的超导相位差耦合到电磁场,由Odintsov-Semenov-Zorin算法。这使我们能够避免在每个时间步计算时间积分,同时考虑所有的记忆效应。为了验证所得到的大约瑟夫森结的微观模型,我们把注意力集中在约瑟夫森磁通流振荡器。所提出的磁通流振荡器的微观模型不涉及唯象阻尼参数,而是在给定温度下计算的隧道电流幅值中自然地考虑阻尼。理论计算的电流-电压特性进行比较,我们的实验结果得到一组制造的磁通流振荡器的不同长度。我们的理论计算与实验结果符合得很好,据我们所知,是第一个约瑟夫森磁通流振荡器的理论描述带来的扰动sine-Gordon方程。

英文摘要:

We elaborate a theoretical description of large Josephson junctions which is based on the Werthamer's microscopic tunneling theory. The model naturally incorporates coupling of electromagnetic radiation to the tunnel currents and, therefore, is particularly suitable for description of the self-coupling effect in Josephson junction. In our numerical calculations we treat the arising integro-differential equation, which describes temporal evolution of the superconducting phase difference coupled to the electromagnetic field, by the Odintsov-Semenov-Zorin algorithm. This allows us to avoid evaluation of the time integrals at each time step while taking into account all the memory effects. To validate the obtained microscopic model of large Josephson junction we focus our attention on the Josephson flux flow oscillator. The proposed microscopic model of flux flow oscillator does not involve the phenomenological damping parameter, rather, the damping is taken into account naturally in the tunnel current amplitudes calculated at a given temperature. The theoretically calculated current-voltage characteristics is compared to our experimental results obtained for a set of fabricated flux flow oscillators of different lengths. Our theoretical calculation agrees well with the obtained experimental results, and, to our knowledge, is the first where theoretical description of Josephson flux flow oscillator is brought beyond the perturbed sine-Gordon equation.

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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