Intrinsic Josephson Junctions and their Terahertz Functions

本征约瑟夫森结及其太赫兹函数

基本信息

批准号：
14350176
负责人：
NAKAJIMA Kensuke
金额：
$ 9.66万
依托单位：
Hirosaki University (2003-2004)Tohoku University (2002)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

项目摘要

High-Tc superconducting cup per oxides (HTSC) show strong anisotropies due to their layered crystal structures consisting of the superconducting CuO_2 layers and the insulating or normal conducting layers in between them. In particular, current transport behaviors across the layers are governed by Josephson weak coupling and are termed the intrinsic Josephson effects. Junction devices fabricated of the HTSC single crystals to use the intrinsic Josephson effects are the intrinsic Josephson junctions (IJJ). The IJJ is the only HTSC Josephson device which can exploit the large energy gaps characteristic of the HTSC and expected to be useful devices operating at very high frequencies up to the terahertz regime. This research project aims to reveals high frequency properties of IJJ to develop superconducting solid state devices for detection and oscillation of terahertz waves. We study (1)precise control of junction properties and (2)effects of externally applied electromagnetic waves on th … More e collective motion of Josephson vortices in the IJJ.For (1), we develop a novel method to control the junction properties by the ion implantation of impurities with strong oxygen affinities.For(2), we succeeded to observe high frequency responses on the vortex flow state which is generated by a flux-flow experiment system designed for this research consisting of a compact cryo-cooler and permanent magnets. By using this system, we found a remarkable zero-crossing step that indicates phase-locking of moving Josephson vortices to the externally applied electromagnetic waves. This results is quite important because it is evident that the electromagnetic waves drives Josephson vortices or vice versa and applicable to amplification and oscillation of terahertz waves by using IJJ. Furthermore, we found periodic potentials introduced in the IJJ along the direction of vortex motion is effective to develop the in-phase coherent motion of the Josephson vortices over the IJJ that is a key point to realize the efficient emission of electromagnetic waves from the IJJ. Less

每氧化物（HTSC）高-TC超导杯显示出强大的各向异性，因为它们的分层晶体结构由超导cuo_2层组成以及它们之间的绝缘或正常导电层。特别是，整个层的当前运输行为受约瑟夫森弱耦合约束，并被称为内在的约瑟夫森效应。固有的约瑟夫森连接（IJJ）是由HTSC单晶制造的结合设备。 IJJ是唯一可以探索HTSC的较大能量差距的HTSC Josephson设备，并且预计将是在Terahertz策略之前以非常高的频率运行的有用设备。该研究项目旨在揭示IJJ的高频特性，以开发超导固态设备来检测和振荡Terahertz波。我们研究（1）对连接特性的精确控制和（2）外部应用电磁波对IJJ.FOR（1）中约瑟夫森涡流的更多集体运动的影响（1），我们开发了一种新的方法，以高度的氧化能力来控制与强大的氧气相关的杂物（2），我们可以通过（2）构成（2）的范围来控制连接性能。专为这项研究设计的通量流实验系统由紧凑的冷冻冷却器和永久磁铁组成。通过使用此系统，我们发现了一个显着的零口字步骤，该步骤表明将约瑟夫森涡流到外部施加的电子波的相相。该结果非常重要，因为这证明了电子波驱动约瑟夫森涡流，反之亦然，并且适用于使用IJJ使用IJJ进行扩增和振荡。此外，我们发现沿IJJ沿涡旋运动方向引入的周期性电势有效地开发了IJJ上约瑟夫森涡流的同相相干运动，这是实现从IJJ有效演化的关键点。较少的