Quantum Transport in Two-Dimensional Electron Systems in Super Periodic Structures

超周期结构二维电子系统中的量子输运

基本信息

批准号：
13304025
负责人：
IYE Yasuhiro
金额：
$ 20.55万
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 (A)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2004
项目状态：
已结题

项目摘要

We carried out a systematic study of quantum oscillatory phenomena in triangular antidot lattices based on two-dimensional electron gas(2DEG) at semiconductor heterointerface. We have observed three different types of quantum interference effects, ---Altshuler-Aronov-Spivak(AAS) oscillation and Aharonov-Bohm(AB) type oscillation near zero field and another type of AB-type oscillation in the quantum Hall regime. We measured their temperature dependences, and elucidated the differences in the decoherence mechanisms. The gate bias dependence of the high field AB-type oscillation furnished information on the self-consistent screened potential formed around the antidots.We studied electron transport under spatial gradient of magnetic field in 2DEG quantum wire decorated with mesoscopic ferromagnetic wire, and found (1)asymmetric conduction and rectifying effect, (2)universal conductance fluctuation in spatially varying magnetic field, and (3)magnetic barrier effect in the quantum Hall regim … More e.We have uncovered a novel magnetoresistance oscillation in short period unidirectional lateral superlattices, which occurred in the lower magnetic field range than the so-called commensurability oscillations. From the analysis of its dependence on the electron density and modulation period, we concluded that the phenomenon is due to geometrical resonance of open orbits with the modulation period. The open orbits are created by Bragg reflection from the lateral superlattice, so this is a clear demonstration of the mini-gap formation. We have also established the method to quantify the modulation amplitude at the 2DEG plane from the analysis of the commensurability oscillation of magnetoresistance.The Little-Parks oscillation of a superconducting wire network subjected to a spatially alternating magnetic flux pattern was investigated. The evolution of the oscillation pattern as a function of the amplitude of the alternation field and that of the uniform field was shown to agree well with the spectral edge of the corresponding Hofstadter butterflies. Less

我们对基于半导体异源面的二维电子气体（2DEG）的三角解毒晶格中的量子振荡现象进行了系统研究。我们已经观察到三种不同类型的量子干扰效应：--- altshuler-aronov-spivak（AAS）振荡和aharonov-bohm（AB）在零场附近的型振荡以及量子霍尔制度中另一种类型的AB-type振荡。我们测量了它们的温度依赖性，并阐明了脱碳机制的差异。高场Ab-type振荡的闸门偏差依赖性提供了有关在解毒剂周围形成的自洽筛选电位的信息。我们在2级量子电线的空间磁场下进行了电子传输，并用中镜量子磁场的空间梯度用中镜下的铁磁性电线和范围内的fluct fort（1）fluct fluct（1）效率（1）效率（2）效率（2）（3）量子大厅方案中的磁性屏障效应……更多的E.我们在短时间单向侧向超级晶格中发现了一种新型的磁性振荡，该磁场发生在磁场范围内的磁场范围比所谓的可分解性振荡。从对电子密度和调制周期的依赖性分析，我们得出的结论是，这种现象是由于调制周期的开放轨道的几何共鸣引起的。开放的轨道是通过横向超晶格的布拉格反射创建的，因此这清楚地证明了迷你间隙形成。我们还建立了一种方法，可以通过分析磁磁性的分析来量化2卡平面的调制放大器。研究了经过空间替代磁性通量模式的超导线网络的小公园振荡。振荡模式与替代场的放大器和均匀场的函数的函数相同，这表明与相应的霍夫斯塔特蝴蝶的光谱边缘非常吻合。较少的