时间：2023年9月14日（周四）下午14:00-15:30

Time：14:00-15:30, Thursday, September 14^th, 2023

主持人: 西湖大学理学院吴颉博士

Host: Dr. Jie Wu, PI of School of Science, Westlake University

地址：西湖大学云谷校区E10-211教室

Venue: Room E10-211, Yungu Campus

李世燕教授

复旦大学

Prof. Shiyan Li

Fudan University

主讲人/Speaker：

Prof. Shiyan Li got his B.S. in 1997 and Ph. D in 2002 at USTC. Then he did postdoc research at University of Toronto/University of Sherbrooke, Canada. In 2007, he joined Fudan University. His current research interests include superconductors, quantum spin liquids, and topological materials. He has published more than 130 papers, including 24 in PRL/PRX, 7 in Nat. Phys./Nano./Comm., 2 in PNAS, and 2 in JACS. He was awarded the 2015 Sir Martin Wood China Prize. His research was supported by NSFC for Excellent Young Scientists. He was appointed “Eastern Scholar” and “Changjiang Scholar”.

讲座摘要/Abstract:

We successfully fabricate ultrathin flakes of iron-based superconductor CsCa2Fe4As4F2 down to monolayer. As the flake thickness decreases, the superconducting transition temperature (TC) initially maintains unchanged (about 30 K) until 4 layers, and then decreases to 19.6 K for the monolayer. The ultrathin limit brings the 2D nature of the superconductivity, which is revealed by the signature of Berezinskii-Kosterlitz-Thouless transition. The reduction of TC is attributed to hole doping and dimension reduction. Our results establish monolayer CsCa2Fe4As4F2 as a new platform to investigate superconductivity in the 2D limit. I will also discuss a rare non-monotonic evolution of the charge-density-wave temperature (TCDW) with the reduction of flake thickness approaching the atomic limit, and the TC features an inverse variation with TCDW in kagome superconductor CsV3Sb5.

讲座联系人/Contact:

理学院，钟梦真，邮箱：zhongmengzhen@westlake.edu.cn

School of Science, Mengzhen Zhong, Email: zhongmengzhen@westlake.edu.cn