arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1508.03085cond-mat.mes-hall
收藏

调制掺杂GaAs/AlGaAs异质结上分裂栅尺寸对一维量子线内静电势和0.7反常的影响

The effect of split gate size on the electrostatic potential and 0.7 anomaly within one-dimensional quantum wires on a modulation doped GaAs/AlGaAs heterostructure

L. W. Smith, H. Al-Taie, A. A. J. Lesage, K. J. Thomas, F. Sfigakis, P. See, J. P. Griffiths, I. Farrer, G. A. C. Jones, D. A. Ritchie, M. J. Kelly, C. G. Smith

摘要:

我们研究了95个不同大小的分裂门在一个单一的芯片上使用多路复用技术。每个分裂栅在调制掺杂的GaAs/AlGaAs异质结构上限定一维沟道,通过该沟道电导被量化。表现出良好量化的器件的产量随着分裂门长度的增加而迅速下降。然而,对于示出良好量化的器件的子集,在一维沟道的静电长度(使用鞍点模型估计)与栅极长度之间不存在相关性。相同栅极长度的器件的静电长度和一维子带间距的变化超过了不同长度的器件之间的平均值的变化。在传输方向上的势垒曲率和“0.7异常”的强度之间存在明显的相关性:0.7异常的电导值随着势垒曲率变浅而减小。这些结果突出了静电环境在一维系统中的关键作用。即使在具有干净的电导平台的器件中,背景电势的随机波动在确定有源器件区域中的电势景观中也是至关重要的,使得名义上相同的栅极结构具有不同的特性。

英文摘要:

We study 95 split gates of different size on a single chip using a multiplexing technique. Each split gate defines a one-dimensional channel on a modulation-doped GaAs/AlGaAs heterostructure, through which the conductance is quantized. The yield of devices showing good quantization decreases rapidly as the length of the split gates increases. However, for the subset of devices showing good quantization, there is no correlation between the electrostatic length of the one dimensional channel (estimated using a saddle point model), and the gate length. The variation in electrostatic length and the one-dimensional subband spacing for devices of the same gate length exceeds the variation in the average values between devices of different length. There is a clear correlation between the curvature of the potential barrier in the transport direction and the strength of the "0.7 anomaly": the conductance value of the 0.7 anomaly reduces as the barrier curvature becomes shallower. These results highlight the key role of the electrostatic environment in one-dimensional systems. Even in devices with clean conductance plateaus, random fluctuations in the background potential are crucial in determining the potential landscape in the active device area such that nominally identical gate structures have different characteristics.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑