Screening model of metallic nonideal contacts in the integer quantized Hall regime
Screening model of metallic nonideal contacts in the integer quantized Hall regime
复制标题
整数量子化霍尔体系中金属非理想接触的筛选模型
DOI：
10.1103/physrevb.82.165308
复制
发表时间：
2010
影响因子：
3.7
通讯作者：
A. Siddiki
中科院分区：
文献类型：
--
作者：
D. Eksi;O. Kilicoglu;O. Goektas;A. Siddiki;A. Siddiki
在这项工作中，我们计算的电子和电流密度分布的边缘和体积的二维电子系统，专注于理想和非理想的接触。一个三维泊松方程求解自洽获得潜在的分布在没有外部磁场的情况下，考虑由栅极（接触）和蚀刻（横向约束）定义的霍尔酒吧。在垂直磁场的存在下，我们得到的不可压缩带的空间分布，考虑到电子-电子相互作用内的B-F近似。使用当地版本的欧姆定律，连同相关的电导率模型，我们还计算了电流分布。我们观察到，不可压缩的带可以驻留在边缘或在体积取决于场强。我们的数值结果表明，由于密度差的区域就在前面的接触，不可压缩带不直接接触的注射区域时，考虑非理想的接触配置。这种非理想接触与传统的边缘通道图像形成强烈的对比，因此对输运具有强烈的影响。我们还考虑到热效应的唯象方式，并提出了一个电流注入机制，从可压缩区域的不可压缩区域。本文提出的模型与局部探测实验结果完全一致，并伴有热点的形成。
In this work, we calculate the electron and the current-density distributions both at the edges and the bulk of a two-dimensional electron system, focusing on ideal and nonideal contacts. A three-dimensional Poisson equation is solved self-consistently to obtain the potential profile in the absence of an external magnetic field considering a Hall bar defined both by gates (contacts) and etching (lateral confinement). In the presence of a perpendicular magnetic field, we obtain the spatial distribution of the incompressible strips, taking into account the electron-electron interactions within the Thomas-Fermi approximation. Using a local version of Ohm's law, together with a relevant conductivity model, we also calculate the current distribution. We observe that the incompressible strips can reside either on the edge or at the bulk depending on the field strength. Our numerical results show that, due to a density poor region just in front of the contacts, the incompressible strips are not in direct contact with the injection region when considering nonideal contact configuration. Such a nonideal contact is in strong contrast with the conventional edge channel pictures, hence has a strong influence on transport. We also take into account heating effects in a phenomenological manner and propose a current injection mechanism from the compressible regions to the incompressible regions. The model presented here perfectly agrees with the local probe experiments all together with the formation of hot-spots.