摘要

大量实验表明，在外延的MoSe2 单层薄膜中会自发形成大量的镜面畴界，而该畴界表现为一维金属，其低能激发态呈现出一系列奇特物性。其中一个比较明显的实验特征为空间电荷周期调制，其起源在文献中已提出不同的建议，如量子限制效应、电荷密度波、Moiré效应、 Luttinger 液体等等。我们通过选择不同衬底进行MoSe2薄膜外延生长、通过调节生长条件控制MoSe2薄膜中镜面畴界的长度，并对其进行细致的低温扫描隧穿电镜及谱的测量，从而确立一维畴界之电子金属态的量子限制效应和Friedel 震荡是实验上观测到的空间电荷调制的主要原因，而且，在石墨或石墨烯上的MoSe2畴界，其低能激发态与Luttinger液体行为一致，而在金衬底上的同类畴界更像费米液体。我们基本上排除了Peierls电荷密度波的贡献。

报告人简介

Prof. XIE received his bachelor degree in electronic engineering from Tianjin University in 1985, master degree in physics from Institute of Semiconductors, Chinese Academy of Sciences, in 1988, and PhD in physics from University of London (Imperial College) in 1994. He worked as a postdoctoral research fellow at Imperial College, London from 1995 to 1997 before joining Physics Department, The University of Hong Kong in 1997 as an assistant professor, then associate and full professor. He served as the head of the Department between Jan. 2017 and Dec. 2019. He also served as the President of Hong Kong Physical Society from 2009 to 2013. Professor Xie’s research is on experimental condensed matter physics, specifically on thin film growth by molecular-beam epitaxy, surface characterizations by scanning tunneling microscopy, electron diffraction, and photoelectron spectroscopy. His research topics include epitaxial thin films and heterostructures of semiconductor (e.g., GaAs/InGaAs, Si/SiGe, GaN/InGaN), topological insulator (e.g., Bi2Se3), and lately on two-dimensional transition-metal dichalcogenides (e.g., MoSe2, WSe2, and MoTe2). He has published over 150 journal papers.