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arXiv 0704.3892cond-mat.mes-hall
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量子点接触中的电流噪声

Current Noise in Quantum Point Contacts

L. DiCarlo, Yiming Zhang, D. T. McClure, D. J. Reilly, C. M. Marcus, L. N. Pfeiffer, K. W. West, M. P. Hanson, A. C. Gossard

摘要:

我们提出了量子点接触的电流噪声作为源漏偏置,栅极电压,和面内磁场的函数的测量。在零偏压下,约翰逊噪声提供了电子温度的测量。在有限偏压下,零场的散粒噪声表现出与电导中的0.7结构相关的不对称性。噪声中的不对称性在高场下平滑地演变为自旋分辨电子传输的对称特征。与密度依赖能级分裂的唯象模型的比较产生了定量的一致性。此外,特定于设备的贡献有限偏置噪声,特别是可见的电导高原(散粒噪声消失),同意定量偏置依赖电子加热的模型。

英文摘要:

We present measurements of current noise in quantum point contacts as a function of source-drain bias, gate voltage, and in-plane magnetic field. At zero bias, Johnson noise provides a measure of the electron temperature. At finite bias, shot noise at zero field exhibits an asymmetry related to the 0.7 structure in conductance. The asymmetry in noise evolves smoothly into the symmetric signature of spin-resolved electron transmission at high field. Comparison to a phenomenological model with density-dependent level splitting yields quantitative agreement. Additionally, a device-specific contribution to the finite-bias noise, particularly visible on conductance plateaus (where shot noise vanishes), agrees quantitatively with a model of bias-dependent electron heating.

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