发表机构
Atlas University Vocational School（阿特拉斯大学职业学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究通过二维自洽屏蔽计算，揭示了窄量子霍尔棒中内部接触在磁场变化下的三种状态，并阐明了隔离电阻的机制及其对参数的敏感性。
AI 中文摘要
我们提出了全二维自洽计算，针对宽度 W = 3 微米的六端 GaAs/AlGaAs 霍尔棒中的电子密度、局域填充因子和电流分布，该霍尔棒带有两个额外的方形接触 A 和 B，位于通道轴上并通过空气桥连接到外部，遵循 Kendirlik 等人的内部接触实验 [Nat. Commun. 8, 14082 (2017)]。在整数量子霍尔效应的屏蔽理论框架内，我们在整个器件平面上求解 Thomas-Fermi-Poisson 方程，包括探测臂和内部接触周围的耗尽区，并通过具有填充因子依赖的电导率张量的局域欧姆定律，分别针对源-漏激励和内部接触激励获得电流。在 nu = 2 平台内，随着磁场降低，内部接触经历三个区域：通过可压缩体电流路径电流性连接，在完全不可压缩体中悬浮于霍尔电势，以及被围绕每个接触的闭合不可压缩环与体和边缘条带隔离。在悬浮和隔离区域中，内部接触之间的两端电阻上升数个数量级。隔离区间位于霍尔平台内，并在其低场边缘之前结束；其高场端由不可压缩体的消失明确设定，而其低场端随温度和朗道能级展宽而缩小。内部接触与周边探针之间的电阻在平台内接近量子化霍尔电阻的一半。不可压缩区域的拓扑结构和隔离区间的边界对局域电导率的正则化、网格和中等无序不敏感，而隔离电阻的大小则不然。
英文摘要
We present fully two-dimensional self-consistent calculations of the electron density, local filling factor and current distribution in a six-terminal GaAs/AlGaAs Hall bar of width W = 3 micrometers with two additional square contacts, A and B, placed on the channel axis and connected to the outside by air bridges, following the interior-contact experiment of Kendirlik et al. [Nat. Commun. 8, 14082 (2017)]. Within the screening theory of the integer quantized Hall effect, the Thomas-Fermi-Poisson equations are solved on the full device plane, including the probe arms and the depletion regions around the interior contacts, and the current is obtained from a local Ohm's law with a filling-factor dependent conductivity tensor, for source-drain and interior-contact excitation separately. Across the nu = 2 plateau the interior contacts pass through three regimes as the field is lowered: galvanically connected to the current path in a compressible bulk, floating in the Hall potential of a fully incompressible bulk, and isolated from both the bulk and the edge strips by closed incompressible rings encircling each contact. In the floating and isolated regimes the two-terminal resistance between the interior contacts rises by orders of magnitude. The isolation interval lies within the Hall plateau and ends before its low-field edge; its high-field end is sharply set by the disappearance of the incompressible bulk, while its low-field end shrinks with temperature and Landau-level broadening. The resistance between an interior contact and a perimeter probe approaches one half of the quantized Hall resistance across the plateau. The topology of the incompressible regions and the boundaries of the isolation interval are insensitive to the regularization of the local conductivity, to the grid and to moderate disorder, whereas the magnitude of the isolation resistance is not.
Comments11 Figures, floow up of NatComm. Paper
