报告人题目：Spin transport in ultrafast demagnetization and terahertz emission

报告人：袁喆 教授（北京师范大学）

报告时间：2019 年 12 月 10 日（周二）15：00 -- 16：00

报告地点：北洋园校区32教218室

报告人摘要：

The spin- and energy-dependent interface reflectivity of a ferromagnetic (FM) film in contact with a nonmagnetic (NM) film is calculated using a first-principles transport method and incorporated into the superdiffusive spin transport model to study the femtosecond laser-induced ultrafast demagnetization of Fe|NM and Ni|NM (NM= Au, Al & Pt) bilayers. By comparing the calculated demagnetization with transparent and real interfaces, we demonstrate that the spin-dependent reflection of hot electrons has a noticeable influence on the ultrafast demagnetization and the associated terahertz electromagnetic radiation. In particular, a spin filtering effect is found at the Fe|NM interface that increases the spin current injected into the NM metal, which enhances both the resulting demagnetization and the resulting THz emission. This suggests that the THz radiation can be optimized by tailoring the interface, indicating a very large tunability. In the last part of this talk, I will review the recent progress in the spintronics neuromorphic computing.

报告人简介：袁喆，北京师范大学物理学系教授，在清华大学物理系就读本科和研究生；获瑞典Chalmers理工大学博士学位；随后在中科院物理研究所，荷兰Twente大学，德国Mainz大学等机构工作；2015年入职北京师范大学；目前主要从事自旋类脑计算、量子自旋输运的理论与数值计算方面研究。