国际合作中心报告 2023年第15期
题目: Electronic Structures and Magnetic Transitions via Layer Control in Two-Dimensional Ferromagnetic van der Waals Films
时间: 2023年09月08日 10:00
地点: 物理所 M楼253会议室
报告人: Prof. Ke Zou

University of British Columbia (UBC)

腾讯会议ID:  593-793-303

会议密码:0908

Abstract:

Fe3GeTe2 (FGT) has garnered significant attention due to its intriguing properties, particularly its two-dimensional (2D) itinerant magnetism and correlated behavior. Experimental investigations have confirmed the tunability of the Curie temperature (TC) of FGT through adjustments in layer number and carrier concentration. Nonetheless, the underlying mechanisms driving these observations remain enigmatic. Theoretical calculations have indicated potential electronic band structures in FGT, suggesting the emergence of topological bands in multilayers due to interlayer coupling. However, our present empirical comprehension of these phenomena, particularly at the monolayer and multilayer scales, remains constrained.

In this study, we employed molecular beam epitaxy (MBE) to meticulously grow high-quality, stoichiometric FGT films with precise layer control, extending down to monolayer thickness. Through angle-resolved photoemission spectroscopy (ARPES), we discerned distinct features in the band structures during the transition of FGT from monolayer to bilayer configurations. These findings were substantiated by density functional theory (DFT) calculations. Additionally, we explored the evolution of carrier density concerning sample thickness and temperature. By conducting an intricate comparison with theoretical predictions, we established a direct correlation linking carrier concentrations, band structures, and the onset of ferromagnetic phase transitions. Our research delivers valuable insights into the fundamental characteristics of this 2D van der Waals ferromagnetic material.

Brief CV of Prof. Ke Zou:

Professor Ke Zou currently holds the position of Assistant Professor within the Department of Physics and Astronomy and the Quantum Matter Institute (QMI) at the University of British Columbia (UBC), a role he has fulfilled since 2018. Prior to this, he served as a Postdoctoral Associate within the Department of Applied Physics at Yale University. Dr. Zou earned his Ph.D. in Physics from Pennsylvania State University in 2012. In 2018, Dr. Zou established a molecular beam epitaxy synthesis laboratory at UBC, equipped with unique infrastructure. This specialized setup is dedicated to material and device development as part of his research endeavors. The overarching goal of this project is to achieve both scientific and technological breakthroughs by leveraging diverse materials at the nanoscale.

邀  请  人:程智刚  特聘研究员

联  系  人:傅    琦(82649469)