新闻动态
·综合新闻
·科研动态
·学术活动
·媒体聚焦
·通知公告
您现在的位置:首页 > 新闻动态 > 学术活动
7.17-19】Ran Cheng
题目: Tutorial session: Berry phase and...
 
2013-07-16 | 文章来源:磁性材料与磁学研究部        【 】【打印】【关闭

题目: Tutorial session: Berry phase and effective magnetic field in electron transport (Part I and Part II)

主讲人: Ran Cheng(程然)

单位:Department of Physics, University of Texas, Austin, TX 78712, USA

时间: 2013年7月17日(周三)10:00-11:30 (Part I)

   2013年7月19日(周五)10:00-11:30 (Part II)

地点: 李薰楼457房间

Abstract:

Berry phase effects affect electron dynamics significantly when the topology of Brillouin zone is non-trivial. In this tutorial, I briefly introduce basic concepts about the quantum geometric phase (Berry phase) and its consequences in transport properties of Bloch electron.
------------------------------------------------------------------------- 

题目: Dynamics of antiferromagnets driven by spin current

主讲人: Ran Cheng

单位:Department of Physics, University of Texas, Austin, TX 78712, USA

时间: 2013年7月18日(周四) 14:00-17:00

地点: 李薰楼468房间

Abstract:

When a spin-polarized current flows through a ferromagnetic (FM) metal, angular momentum is transferred to the magnetization via spin transfer torques. In antiferromagnetic (AFM) materials, however, the corresponding problem is unsolved. We derive microscopically the dynamics of an AFM system driven by spin current generated by an attached FM polarizer, and find that the spin current exerts a driving force on the local staggered order parameter. The mechanism does not rely on the conservation of spin angular momentum, nor does it depend on the induced FM moments on top the AFM background. Two examples are studied: (i) A domain wall is accelerated to a terminal velocity by purely adiabatic effect and no Walker's break-down exists. (ii) Injection of spin imbalance significantly splits the spin wave spectrum; a spin current triggers spin wave instability above a threshold that depends on the ratio between the spin imbalance and anisotropy gap.

欢迎参加!

文档附件

相关信息
联系我们 | 友情链接
地址: 沈阳市沈河区文化路72号 邮编: 110016
运维邮箱: office@imr.ac.cn
中国科学院金属研究所 版权所有 辽ICP备05005387号-1

官方微博

官方微信