Noise processes in InAs/Ga(In)Sb Corbino structures
Noise processes in InAs/Ga(In)Sb Corbino structures
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DOI：
10.1063/1.5111626
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发表时间：
2019-08
影响因子：
4
通讯作者：
Loah A. Stevens;Tingxin Li;R. Du;D. Natelson
中科院分区：
文献类型：
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作者：
Loah A. Stevens;Tingxin Li;R. Du;D. Natelson
二维拓扑绝缘体是人们非常感兴趣的，预测的拓扑保护一维螺旋边缘状态在其边界。散粒噪声，驱动电流的波动，由于电荷载流子的离散性，已被提出作为一种区分平凡和非平凡的边缘状态传导，以及评估后向散射机制在后者的一种手段。这样的测量需要了解接触和2D块体中的传导对噪声的可能贡献。我们提出了噪声测量的Corbino结构的基础上InAs/Ga（In）Sb量子阱界面在较宽的温度和电流范围内。随着温度的降低和批量运输的间隙，散粒噪声变得可检测到在这些双端设备，在高频和低频测量技术。与噪声模型的定量比较表明，总施加电压降在接触点和体之间分配，并且器件具有一些固有的不对称性。在该模型中，散粒噪声的幅度似乎非常大，这意味着在该系统中与2D块体的接触是不平凡的。
Two-dimensional topological insulators are of great interest, with predicted topological protection of one-dimensional helical edge states at their boundaries. Shot noise, the fluctuations in driven current due to the discreteness of charge carriers, has been proposed as a way of distinguishing between trivial and nontrivial edge state conduction, as well as a means of assessing back-scattering mechanisms in the latter. Such measurements require an understanding of possible contributions to the noise from contacts and conduction in the 2D bulk. We present noise measurements in Corbino structures based on InAs/Ga(In)Sb quantum well interfaces over a broad temperature and applied current range. As the temperature is lowered and the bulk transport is gapped out, shot noise becomes detectable in these two-terminal devices, in both high- and low-frequency measurement techniques. Quantitative comparison with a noise model shows that the total applied voltage drop is split among the contacts and the bulk and that the devices have some intrinsic asymmetry. Within that model, the magnitude of the shot noise appears to be anomalously large, implying the contacts to the 2D bulk are nontrivial in this system.