铅量子薄膜中量子通道、界面结构和超导的原位电子输运研究

The research and application of low-dimensional quantum systems have made tremendous advancement in the last few decades and it has since played important roles in the development of electronics and spintronics technologies. Among those, Pb quantum thin films have displayed many novel quantum phenomena and attracted huge attentions. However, the in-situ electron transport study is still lacking, which has limited the understanding of this quantum system, and some physical phenomena remained controversial and awaiting to be resolved. This proposal will be focusing on the in-situ electron transport studies, combining scanning tunneling microscopy/spectroscopy measurements, and try to understand the effects of different quantum channels, substrate interfaces, surface conductance, and atomic steps on the electron transport; as well as the correlations between local electron paring and long range ordering in the two-dimensional superconductivity. Try to improve the understanding of the electron transport of the two-dimensional quantum materials and discover the underlying principles, and develop the new functions and applications based on current materials.

低维量子体系的研究和应用在过去几十年间取得了巨大的发展并且对基于电子学和自旋电子学等技术的发展起了重要的作用。其中铅量子薄膜材料由于其展示出多种新奇的量子效应引起人们广泛的兴趣。然而，电子输运方面尤其是原位电子输运方面的研究却非常缺乏，导致该材料体系的一些科学问题得不到圆满解决，甚至一些基本物理现象还存在争议。本研究将围绕原位电子输运测量进行，同时结合扫描隧道显微镜和扫描隧道谱，主要研究不同量子通道、衬底界面、表面电导和原子台阶边界对电子输运的影响；以及二维超导体中局部电子对和超导的长程有序性间的内在关联。希望对二维量子材料中的电子输运有更进一步的认识，并发现其一般规律，推动在现有材料基础上进一步发展新功能和应用。

该项目所取得的开创性的研究成果包括：结合电子输运与扫描隧道显微镜/隧道谱学测量揭示了尺寸、晶界晶畴大小与电学性能的关系，为今后电子器件选用高质量的通道材料提供了新思路；通过使用脉冲阀注入水蒸气脉冲的一种水辅助化学气相沉积过程成功生长AB堆积出双层石墨烯，研究结果对双层石墨烯的工业应用和CVD石墨烯生长机理的阐明具有重要意义；成功制备出一种不匹配化合物(SnS)1.17(NbS2)天然的异质结构并且直接揭示其电子结构，发现其费米能级附近的能带特征由Nbs2单原子层主导，为将来研究单层TMDs的电子结构提供了一种新思路；利用超导针尖与铅超导薄膜形成的SIS结的隧道谱发现使用铅超导针尖可以显著提高dI/dV光谱分辨率，并且观察到约瑟夫森效应等，为该低温STM系统中更精确的温度测量和控制提供了一个重要的参考依据。在该基金的资助下，总共发表高水平SCI论文4篇、并多次国内外做受邀报告。