Numerical study of dephasing in disordered electron systems

无序电子系统失相的数值研究

基本信息

批准号：
14540363
负责人：
OHTSUKI Tomi
金额：
$ 1.98万
依托单位：
Sophia University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2005
项目状态：
已结题

项目摘要

In this project, we have studied numerically dephasing and related topics in quantum transport in disordered electron systems where complex quantum interference plays an important role. The interference is especially important in low dimensional systems such as the 2 dimensional electron system (2DES). The breakdown of the interference due to the coupling to external degrees of freedom such as a heat bath is the origin of dephasing. Attaching extra lead(s) coupled to reservoir(s) is a way to take into account the dephasing in numerical calculations. In this project, therefore, we have studied the following :1) Study of electron transport in the 3 terminal geometry : to take into account the dephasing, study of systems with more than two terminals is needed. We have developed a program to study this issue, and have calculated the transport coefficients. As a byproduct, we have analyzed the generation of spin polarized current in the presence of spin-orbit interaction. (Papers 2 and 4.)2 … More ) Study of the role of spin in quantum transport phenomena : the role of the spin degree of freedom in quantum transport has been studied. Of particular interest is the system with strong spin-orbit scattering in low dimensional systems. We have simulated conductance fluctuations (paper 10), the Anderson transition in 2DES (papers 8 and 15) and the Anderson transition below 2 dimensions (paper 1). Dephasing in the presence of spin-orbit scattering has been studied in the 2DES by assuming a time-dependent potential (paper 14).3) Study of random phase model : to investigate the importance of phase in quantum transport, we have studied the random phase model (papers 6 and 11).4) Study of quantum network model : the network model that is a simplified model to study the quantum transport phenomena has been studied (paper 5). Since the model is simple, we are able to attach many leads to a sample.5) Study of edge states in the quantum Hall effect : the quantum Hall edge states are know to have extraordinary long dephasing time. We have studied these states in the presence of disorder in detail (papers 3 and 7). Less

在这个项目中，我们研究了无序的电子系统中量子传输的数值驱动和相关主题，其中复杂的量子干扰起着重要作用。干扰在低维系统（例如2维电子系统（2DE））中尤为重要。由于耦合到外部自由度（例如热浴）的耦合而引起的干扰崩溃是dephasing的起源。将耦合到Reserver的额外铅（S）附加是一种考虑数值计算中dephasing的方法。因此，在该项目中，我们研究了以下内容：1）研究3末端几何形状中电子传输的研究：要考虑到dephasing，需要对具有两个以上端子的系统进行研究。我们已经制定了一个研究此问题的程序，并计算了运输系数。作为副产品，我们在存在自旋轨道相互作用的情况下分析了自旋极化电流的产生。（论文2和4）2…更多）研究自旋在量子传输现象中的作用：自旋度在量子运输中的作用。特别值得关注的是该系统在低维系统中具有强旋轨道散射。我们模拟了电导波动（论文10），2DES中的安德森过渡（论文8和15）以及安德森过渡以下2维度（论文1）。已经在2DE中研究了在存在自旋轨道散射中的dephasing，它通过假设时间依赖性电位（论文14）.3）研究随机相模型：为了研究量子传输中相的重要性，我们研究了量子网络模型的随机相模型（论文6和11）。网络模型：一种简单的模型，是一种简单的模型来研究量子运输的模型5量子的研究了量子运输的模型5次数。由于模型很简单，因此我们能够将许多导线附加到样品中。5）量子厅效应中边缘状态的研究：量子霍尔边缘状态知道具有非凡的长时间倾向时间。我们在详细存在障碍的情况下研究了这些状态（论文3和7）。较少的