Two-dimensional growth of conductive ultra-thin Sn films on insulating substrate with an Fe buffer layer
Two-dimensional growth of conductive ultra-thin Sn films on insulating substrate with an Fe buffer layer
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DOI：
10.1063/5.0009012
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发表时间：
2020-06
期刊：
影响因子：
6.1
通讯作者：
D. Zheng;J. Shiogai;H. Inoue;S. Souma;Takafumi Sato;A. Tsukazaki
中科院分区：
文献类型：
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作者：
D. Zheng;J. Shiogai;H. Inoue;S. Souma;Takafumi Sato;A. Tsukazaki
二维（2D）生长的超薄锡薄膜是一个先决条件，检查奇异的量子现象，因为它们的结晶形式之一是一个有前途的候选拓扑材料。在这项研究中，我们已经研究了超薄薄膜生长的Sn在室温下与Fe缓冲层的绝缘Al 2 O3衬底上使用分子束外延。通过插入2-或4-nm厚的Fe层，Sn薄膜的生长模式从基于Al 2 O3的三维（3D）岛模式变化到基于Fe的2D层模式。然而，当Sn的厚度（dSn）达到约1.0 nm的临界值dcSn时，3D生长模式重新出现，对应于三个原子层。随着Fe缓冲层上的dSn的增加，片电导的系统性增加揭示了Sn膜的片电导可以表征为小于dcSn的厚度。dcSn以上的片电导的饱和表示通过基于岛的生长模式生长的Sn膜的断开。此外，在Sn/Fe双层的异常霍尔电阻的减少与增加dSn是由于导电超薄2D Sn层的分流和短路效应。通过考虑Sn和Fe之间的强耦合在双层中提供大的异常霍尔效应，进一步优化超薄Sn在Fe上的2D生长将为通过电输运测量研究奇异的界面物理现象铺平道路。
Two-dimensional (2D) growth of ultra-thin Sn films is a prerequisite for examining exotic quantum phenomena as one of their crystallized forms is a promising candidate for topological materials. In this study, we have investigated the ultra-thin film growth of Sn at room temperature with a Fe buffer layer on an insulating Al2O3 substrate using molecular-beam epitaxy. By the insertion of a 2- or 4-nm-thick Fe layer, the growth mode of Sn thin films varies from a three-dimensional (3D) island-based mode on Al2O3 to a 2D layer-based mode on Fe. However, the 3D growth mode reappeared when the thickness of Sn (dSn) reached the critical value dcSn of about 1.0 nm, corresponding to three atomic layers. A systematic increase in the sheet conductance with increasing dSn on the Fe buffer layer revealed that the sheet conductance of the Sn film can be characterized for a thickness less than dcSn. The saturation of the sheet conductance above dcSn indicates a disconnection of the Sn film grown by the island-based growth mode. In addition, the reduction in anomalous Hall resistance in the Sn/Fe bilayer with increasing dSn is attributed to the shunting and short-circuit effects of the conductive ultra-thin 2D Sn layer. By considering the strong coupling between Sn and Fe providing large anomalous Hall effects in the bilayer, further optimization of the 2D growth of ultra-thin Sn on Fe will pave the way to investigate exotic interfacial physical phenomena through electrical transport measurement.