权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Investigation of the Macro Coherence in Bilayer Quantum Hall State by Micro Wave

微波研究双层量子霍尔态的宏观相干性

基本信息

批准号：
14340088
负责人：
SAWADA Anju
金额：
$ 10.05万
依托单位：
KYOTO UNIVERSITY (2004)Tohoku University (2002-2003)
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

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-14340088/
关键词：
Quantum Hall Effect Composite Boson Composite Fermion Interlayer Coherence Activation Energy Gallium Arsenide Pseudospin Spin

项目摘要

We investigated interlayer coherence of the bilayer quantum Hall states. The microwave cryostat was constructed for measurement of Josephson plasmon and then the experiments were done at 2 K. The quantum Hall effects were clearly observed, but Josephson plasmon was not observed. The cause we cannot observe Josephson plasmon is due to the low quality of the sample and the higher temperature. We will soon improve the experimental way to detect Josephson plasmon. The other hand, we get important experimental results for interlayer coherence from transport.(1) : We study a pseudospin (layer degree of freedom) domain structure in bilayer v=1 quantum Hall states by detailed transport measurements in tilted magnetic fields. We find that the magnetoresistance R_<xx> shows a broad peak at the commensurate-incommensurate transition. An extrapolated value of R_<xx> at the peak down to 0 K is finite, showing the existence of a dissipative ground state. From the comparison of B_<//> dependence of R_<xx> and activation energy with theories, we suggest that the origin of the dissipation is pseudospin domain walls in the soliton lattice. This is the first observation in the quantum Hall state that a resistance peak is induced not by the crossing of two Landau levels, but possibly by a number of pseudospin domains, i.e., interlayer phase twists.(2) : We examine an anisotropic transport in a bilayer system around the quantum Hall state at the total Landau level filling factor v=1. We find that the anisotropy becomes remarkable at the phase transition point between the commensurate and incommensurate states. This results that a unidirectional state appears around the transition.

我们研究了双层量子霍尔态的层间相干性。搭建了测量约瑟夫森等离子体激元的微波低温恒温器，并在2K下进行了实验。量子霍尔效应被清楚地观察到，但约瑟夫森等离子体激元没有观察到。我们无法观测到约瑟夫森等离子体激元的原因是由于样品质量差和温度较高。我们将很快改进检测约瑟夫森等离子体激元的实验方法。另一方面，我们从输运的角度得到了层间相干性的重要实验结果。(1):通过详细的输运测量研究了倾斜磁场中双层v=1量子霍尔态的赝自旋畴结构。我们发现，磁阻R_1<xx>在超导体-无公度转变处有一个宽峰。外<xx>推到0 K时，R_（？）的峰值是有限的，表明存在耗散基态。通过与理论结果的比较<xx>，我们认为耗散的起源是孤子晶格中的赝自旋畴壁。这是在量子霍尔态中的第一个观察，即电阻峰不是由两个朗道能级的交叉引起的，而是可能由许多赝自旋畴引起的，即，层间相位扭曲(2)我们研究了在总朗道能级填充因子v=1时双层系统中量子霍尔态周围的各向异性输运。我们发现，在公度态和非公度态之间的相变点，各向异性变得显著。这导致在跃迁周围出现单向状态。