Academy of Scientific and Innovative Research (AcSIR), National Physical Laboratory, Council of Scientific and Industrial Research, Dr. K. S Krishnan Road, New Delhi, 110012, India.
National Physical Laboratory, Council of Scientific and Industrial Research, Dr. K. S Krishnan Road, New Delhi, 110012, India.
Sci Rep. 2017 Aug 10;7(1):7825. doi: 10.1038/s41598-017-08018-6.
We report the experimental observation of variable range hopping conduction in focused-ion-beam (FIB) fabricated ultra-narrow nanowires of topological insulator (BiSe). The value of the exponent (d + 1) in the hopping equation was extracted as [Formula: see text]for different widths of nanowires, which is the proof of the presence of Efros-Shklovskii hopping transport mechanism in a strongly disordered system. High localization lengths (0.5 nm, 20 nm) were calculated for the devices. A careful analysis of the temperature dependent fluctuations present in the magnetoresistance curves, using the standard Universal Conductance Fluctuation theory, indicates the presence of 2D topological surface states. Also, the surface state contribution to the conductance was found very close to one conductance quantum. We believe that our experimental findings shed light on the understanding of quantum transport in disordered topological insulator based nanostructures.
我们报告了在聚焦离子束（FIB）制造的拓扑绝缘体（BiSe）超窄纳米线中观察到的可变范围跳跃传导的实验结果。从不同宽度的纳米线中提取跳跃方程中的指数（d+1）的值为[Formula: see text]，这证明了在强无序系统中存在 Efros-Shklovskii 跳跃输运机制。为器件计算了高局域化长度（0.5nm、20nm）。使用标准的通用电导涨落理论对磁阻曲线中存在的温度相关涨落进行了仔细分析，表明存在 2D 拓扑表面态。此外，还发现表面态对电导的贡献非常接近一个电导量子。我们相信，我们的实验结果为理解基于拓扑绝缘体的无序纳米结构中的量子输运提供了线索。
