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Vortex dynamics in the intrinsic Josephson junction near the quantum regime

量子态附近本征约瑟夫森结中的涡旋动力学

基本信息

批准号：
13640353
负责人：
MATSUDA Yuji
金额：
$ 2.18万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13640353/
关键词：
Josephson junction Flux flow High-Tc superconductor Shapiro step Quantum region Charging effect Superconducting gap Bi : 2212 高温超伝導ジョセフソン効果微細加工ジョセフソンボルテックスマイクロ波クーロンブロッケイド Bi : 2212 フラックスロー有機超伝導

项目摘要

Highly anisotropic high-Tc superconductors, such as Bi : 2212, can be considered as stacks of superconducting CuO_2 layers coupled by the Josephson interaction. Several properties which have never been observed in single Josephson junctions made from conventional low-Tc materials have been found, which are associated with the multilayer structure and with the atomic thickness of the superconducting layers. In particular, the vortex phase diagram and the related electromagnetic properties of HTSC in the presence of a strong magnetic field parallel to the layers have been the subject of recent intense experimental and theoretical studies. In this project, we report the first observation of Shapiro steps in the Josephson flux flow state of Bi : 2212 stacked junctions. When the junction is irradiated at microwave frequencies in a strong parallel magnetic field, a steep increase of the current is observed in the dc current-voltage characteristics when the external microwave frequency and the Josephson frequency are harmonically related. The existence of Shapiro steps in the Josephson flux flow state is strong evidence of coherent motion of the Josephson vortex lattice through the whole thickness of the stack.

高度各向异性的高Tc超导体，如Bi：2212，可以看作是由超导CuO_2层通过Josephson相互作用耦合而成的叠层。在由常规低Tc材料制成的单约瑟夫森结中从未观察到的几个性质已经被发现，这些性质与多层结构和超导层的原子厚度有关。特别是，涡流相图和HTSC在平行于层的强磁场的存在下的相关的电磁特性一直是最近激烈的实验和理论研究的主题。在这个项目中，我们报告的第一次观察到的Shapiro台阶的约瑟夫森磁通流状态的Bi：2212堆叠结。当结在微波频率在一个强的平行磁场中照射时，观察到一个陡峭的电流增加的直流电流-电压特性时，外部微波频率和约瑟夫森频率是谐波相关的。约瑟夫森通量流态中夏皮罗台阶的存在是约瑟夫森涡旋晶格在整个叠层厚度上相干运动的有力证据。