Krupinski Michal, Zarzycki Arkadiusz, Zabila Yevhen, Marszałek Marta
Institute of Nuclear Physics Polish Academy of Sciences, Radzikowskiego 152, 31342 Krakow, Poland.
Materials (Basel). 2020 Jul 22;13(15):3246. doi: 10.3390/ma13153246.
Using a two-carriers model and the Hikami-Larkin-Nagaoka (HLN) theory, we investigate the influence of large area patterning on magnetotransport properties in bismuth thin films with a thickness of 50 nm. The patterned systems have been produced by means of nanospheres lithography complemented by RF-plasma etching leading to highly ordered antidot arrays with the hexagonal symmetry and a variable antidot size. Simultaneous measurements of transverse and longitudinal magnetoresistance in a broad temperature range provided comprehensive data on transport properties and enabled us to extract the values of charge carrier densities and mobilities. Weak antilocalization signatures observed at low temperatures provided information on spin-orbit scattering length ranging from 20 to 30 nm, elastic scattering length of approx. 60 nm, and strong dependence on temperature phase coherence length. We show that in the absence of antidots the charge carrier transport follow 2-dimensional behavior and the dimensionality for phase-coherent processes changes from two to three dimensions at temperature higher than 10 K. For the antidot arrays, however, a decrease of the power law dephasing exponent is observed which is a sign of the 1D-2D crossover caused by the geometry of the system. This results in changes of scattering events probability and phase coherence lengths depending on the antidot diameters, which opens up opportunity to tailor the magnetotransport characteristics.
利用双载流子模型和日高-拉金-永冈（HLN）理论，我们研究了大面积图案化对厚度为50 nm的铋薄膜磁输运性质的影响。图案化系统是通过纳米球光刻技术并辅以射频等离子体蚀刻制备的，从而得到具有六边形对称性且反点尺寸可变的高度有序的反点阵列。在很宽的温度范围内同时测量横向和纵向磁电阻，提供了关于输运性质的全面数据，并使我们能够提取载流子密度和迁移率的值。在低温下观察到的弱反局域化特征提供了关于自旋-轨道散射长度范围为20至30 nm、弹性散射长度约为60 nm以及对温度相位相干长度强烈依赖性的信息。我们表明，在没有反点的情况下，载流子输运遵循二维行为，并且在高于10 K的温度下，相位相干过程的维度从二维变为三维。然而，对于反点阵列，观察到幂律退相指数减小，这是由系统几何结构引起的一维到二维转变的标志。这导致散射事件概率和相位相干长度随反点直径而变化，这为定制磁输运特性提供了机会。
