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Device-Oriented Basic Studies on Coherent Quantum Waves in Josephson Superlattices

约瑟夫森超晶格中相干量子波的面向器件的基础研究

基本信息

批准号：
09831001
负责人：
OYA Ginichiro
金额：
$ 2.11万
依托单位：
Utsunomiya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

项目摘要

The purpose of this study is to establish the fundamentals of quantum effect devices using dynamic behavior of coherent waves of electrons (holes) and flux quanta in natural superlattices of intrinsic Josephson junctions, which consist of superconducting CuOィイD22ィエD2 and insulating BiO/SrO layers, in layered high-temperature oxide-superconductor BiィイD22ィエD2SrィイD22ィエD2CaCuィイD22ィエD2OィイD2yィエD2 single crystals.The results obtained in this study are as follows :1. For rectangular and annular mesas (superlattices) fabricated as basic shapes of the devices from the single crystals, it has been clarified that the coherent motion of flux quanta (Josephson vortices) introduced by applying magnetic fields to the mesas occurs at high rates of (1-5)×10ィイD1-6ィエD1m/s (at 4.2K) by biasing currents to the mesas, which correspond nearly to the highest phase velocity of electromagnetic waves induced in the constituent intrinsic Josephson junctions. Numerical simulations have also shown such a motion of flux quanta in the superlattices.2. For rectangular mesas, it has been found that high frequency oscillations, which take place due to the motion of flux quanta in the intrinsic Josephson junctions, can be controlled by external magnetic fields, and as a result, a high frequency oscillation of 80GHz occurs with a magnetic field of 0.16T at 4.2K.3. For rectangular and annular mesas, it has also been found that the coherent motion of electronic (hole) waves in the intrinsic Josephson junction superlattices can be excited and controlled as in switching devices by current pulses, and then high frequency oscillations of several ten GHz-THz (at 4.2K) can also occur.

本研究的目的是利用层状高温氧化物超导体中的本征约瑟夫森结的自然超晶格中电子（空穴）和通量量子的相干波的动态行为来建立量子效应器件的基础，该约瑟夫森结由超导 CuOiiD22iiD2 和绝缘 BiO/SrO 层组成。 BiィイD22ィエD2SrィイD22ィエD2CaCuィイD22ィエD2OィイD2yィエD2单晶。本研究获得的结果如下： 1．对于作为单晶器件基本形状制造的矩形和环形台面（超晶格），已经阐明，通过向台面施加磁场而引入的通量量子（约瑟夫森涡旋）的相干运动通过向台面施加偏置电流以（1-5）×10ィイD1-6ィD1m/s（4.2K）的高速率发生，这几乎对应于本征约瑟夫森结中感应的电磁波的最高相速度。数值模拟也显示了超晶格中通量量子的这种运动。2．对于矩形台面，人们发现，由于本征约瑟夫森结中磁通量子的运动而发生的高频振荡可以通过外部磁场控制，从而在4.2K.3、0.16T的磁场下发生80GHz的高频振荡。对于矩形和环形台面，还发现本征约瑟夫森结超晶格中的电子（空穴）波的相干运动可以像在开关器件中一样被电流脉冲激发和控制，然后也可以发生数十GHz-THz（4.2K）的高频振荡。